Measurement system with modular measurement modules that convey interface information

ABSTRACT

System and method for measurement, DAQ, and control operations which uses small form-factor measurement modules or cartridges with a re-configurable carrier unit, sensors, and a computer system to provide modular, efficient, cost-effective measurement solutions. The measurement module includes measurement circuitry, e.g., signal conditioner and/or signal conversion circuitry, and interface circuitry for communicating with the carrier unit. The module communicates interface information to the carrier unit, which informs the computer system how to program or configure a functional unit on the carrier unit to implement the communicated interface, or sends the information directly to the computer system. The computer system programs the carrier unit with the interface, and the programmed carrier unit and measurement module together function as a DAQ, measurement, and/or control device. The carrier unit may receive multiple cartridges, each having a respective interface protocol, where the carrier unit is configurable to support the respective protocols sequentially and/or in parallel.

PRIORITY CLAIM

This application claims benefit of priority of U.S. ProvisionalApplication Ser. No. 60/312,254 titled “Measurement System with ModularMeasurement Modules That Convey Interface Information” filed on Aug. 14,2001, whose inventors are Perry Steger, Garritt W. Foote, David Potterand James J. Truchard.

FIELD OF THE INVENTION

The present invention relates to measurement, data acquisition, andcontrol, and particularly to measurement devices with adaptiveinterfaces and modular signal conditioning and conversion devices whichconvey interface information.

DESCRIPTION OF THE RELATED ART

Scientists and engineers often use measurement or instrumentationsystems to perform a variety of functions, including laboratoryresearch, process monitoring and control, data logging, analyticalchemistry, test and analysis of physical phenomena, and control ofmechanical or electrical machinery, to name a few examples. Aninstrumentation system typically includes transducers and otherdetecting means for providing “field” electrical signals representing aprocess, physical phenomena, equipment being monitored or measured, etc.For example, detectors and/or sensors are used to sense the on/off stateof power circuits, proximity switches, pushbutton switches, thermostats,relays or even the presence of positive or negative digital logic-levelsignals. The instrumentation system typically also includes interfacehardware for receiving the measured field signals and providing them toa processing system, such as a personal computer. The processing systemtypically performs data analysis and presentation for appropriatelyanalyzing and displaying the measured data.

Often, the field signals may be coupled to high common-mode voltages,ground loops, or voltage spikes that often occur in industrial orresearch environments which could damage the computer system. In thatcase, the instrumentation system typically includes isolation circuitrysuch as opto-couplers for eliminating ground-loop problems and isolatingthe computer from potentially damaging voltages. Input modules aretypically provided for conditioning the raw field voltage signals byamplifying, isolating, filtering or otherwise converting the signals tothe appropriate digital signals for the computer system. As one example,the digital signals are then provided to a plug-in data acquisition(DAQ) input/output (I/O) board, or a computer-based instrument which isplugged into one of the I/O slots of a computer system. Generally, thecomputer system has an I/O bus and connectors or slots for receiving I/Oboards. Various computer systems and I/O buses may be used to implementa processing system.

Typical DAQ, measurement, and control modules include circuitry orcomponents to provide a standard interface to external systems, such asPCI or PXI boards. The inclusion of these standard interface componentson each module may be expensive, and may also substantially increase thesize of a given module. Additionally, when multiple modules are used ina single system, such as a PXI based system fielding multiple sensors,the inclusion of PXI interface circuitry on each sensor is redundant andinefficient. Finally, if multiple communication interfaces are desiredfor the modules, the expense and size of the modules may increasedramatically with the inclusion of each additional interface card.

Therefore, improved measurement systems are desired which reduce costand enhance efficiency and flexibility.

SUMMARY

Various embodiments of a system and method for measurement, DAQ, andcontrol operations are described. The system may use small form-factormeasurement modules in conjunction with a re-configurable carrier unit,sensors and a computer system to provide modular, efficient,cost-effective measurement solutions. In one embodiment, the measurementmodule is operable to communicate interface information to the carrier,which in turn informs the computer system how to program the carrier toimplement the communicated interface, i.e., how to “talk” to themeasurement module. In another embodiment, the carrier itself mayinclude a processor and memory which receives the interface informationfrom the module and programs reconfigurable hardware on the carrier toimplement the interface.

This “adaptive interface” approach allows the measurement module toinclude only components necessary for providing the requiredfunctionality, i.e., the measurement module does not have to includehardware and software implementing standard interfaces for communicationwith external systems. Said another way, much of the interfaceresponsibilities of the measurement module are assumed by the carrier,which itself is programmed by the computer system, thus the measurementmodule may be smaller and cheaper than typical functional modules. Inthe preferred embodiment, the measurement module has a small formfactor. For example, in one embodiment, the measurement module may havedimensions less than or equal to approximately 1 inch by 2 inches by 3inches. In one embodiment, the measurement module may have dimensions ofapproximately 0.2 inches by 1 inch by 1 inch or more. Thus, in apreferred embodiment, the measurement module has a compact form factorwhich may enable deployment in a variety of devices or carriers withminimal space requirements.

A typical measurement system using this approach includes a computersystem coupled to a measurement or data acquisition (DAQ) device, whichmay include a carrier and one or more measurement modules. As usedherein, the term “measurement device” is intended to include any ofvarious types of devices that are operable to acquire and/or store data,and which may optionally be further operable to analyze or process theacquired or stored data. Examples of a measurement device includevarious types of instruments, such as oscilloscopes, multimeters a dataacquisition device or card, a device external to a computer thatoperates similarly to a data acquisition card, a smart sensor, one ormore DAQ or measurement modules in a chassis, and other similar types ofdevices. The computer system may couple to the measurement devicethrough a serial bus, such as a USB (Universal Serial Bus), or any othermedium including Ethernet, wireless media such as IEEE 802.11 (WirelessEthernet) Bluetooth, a network, such as a Control Area Network (CAN) orthe Internet, serial or parallel buses, or any other transmission means.

The host computer may comprise a CPU, a display screen, memory, and oneor more input devices such as a mouse or keyboard, and may operate withthe measurement device to analyze or measure data from thesensor/measurement device or to control the sensor and/or device.Alternatively, the computer may be used only to configure or program themeasurement device, i.e., the carrier, as described below.

In one embodiment, the measurement module may include measurementcircuitry which is operable to perform signal conditioning and/or signalconversion, e.g., a signal conditioner and/or a signal converter, suchas an analog to digital converter (ADC) or a digital to analogconverter. The measurement module may also include interface circuitrywhich is operable to provide an interface for the measurement circuitry,and which may also be operable to communicate an interface protocol tothe carrier unit describing the interface, as mentioned above. Themeasurement module may also include additional transmission lines and/orbuses for operation, e.g., a trigger line coupled to the ADC which mayreceive trigger signals from an external source, such as the computersystem, and a power line for supplying power to the measurement module.

The measurement module may be further operable to couple to a sensor oractuator. The sensor may receive signals from a device or unit undertest (UUT) and may send sensor signals to the measurement module for oneor more of signal conditioning and signal conversion. For example, thesensor may measure a phenomenon, such as temperature, pressure, voltage,current, or any other phenomenon, and send signals to the measurementmodule. The signal conditioner comprised in the measurement module maythen perform signal conditioning on the signals, where signalconditioning may include one or more of protection, isolation,filtering, amplification, and excitation, or other signal conditioningoperations. The conditioned signals may then be processed by the signalconverter, also comprised in the measurement module, which may beoperable to perform one or more of analog to digital (A/D) conversionand digital to analog (D/A) conversion of the signal, depending onwhether the signal is analog or digital. The conditioned, convertedsignals may then be transmitted by the interface circuitry to thecarrier using the specified interface protocol. In other words, themeasurement module may transmit the conditioned, converted signals tothe carrier over the serial transmission medium SPI. The carrier maythen further analyze the signals or transmit the signals to an externalsystem, such as computer system.

In a preferred embodiment, the carrier includes a functional unit, e.g.,a processor and memory or a programmable hardware element, which may beprogrammed by the computer system, or in other embodiments, by aprocessor and memory on the carrier. As used herein, the term“processor” is intended to include any of types of processors, CPUs,microcontrollers, or other devices capable of executing softwareinstructions. As used herein, the term “programmable hardware element”is intended to include various types of programmable hardware,reconfigurable hardware, programmable logic, or field-programmabledevices (FPDs), such as one or more FPGAs (Field Programmable GateArrays), or one or more PLDs (Programmable Logic Devices), such as oneor more Simple PLDs (SPLDs) or one or more Complex PLDs (CPLDs), orother types of programmable hardware.

As mentioned above, the carrier unit is operable to receive interfaceprotocol information from the measurement module specifying how tooperate or interface with the measurement module. In one embodiment, thecarrier unit may then communicate the interface protocol information tothe computer system. Alternatively, the measurement module maycommunicate the interface protocol information directly to the computersystem. Based on the interface protocol information, the computer systemmay program or configure the functional unit on the carrier unit toimplement the interface as specified by the measurement module. In otherwords, the measurement module may tell the carrier how to “talk” withit, and the carrier may then tell the computer system how to program thecarrier to communicate with the measurement module accordingly (or themeasurement module may tell the computer system directly how to programthe carrier). The computer system may then program the carrier (i.e.,the carrier's functional unit), thereby implementing the interfacespecified in the interface protocol information communicated by themeasurement module.

As noted above, in another embodiment, the carrier unit may be operableto receive the interface protocol information from the measurementmodule, and a processor and memory on the carrier unit may then programor configure the functional unit on the carrier unit to implement theinterface as specified by the measurement module. In other words, themeasurement module may communicate its interface protocol to thecarrier, and the carrier may program itself (i.e., a processor/memory onthe carrier may program a programmable hardware element) to communicatewith the measurement module accordingly, thereby implementing theinterface specified in the interface protocol information communicatedby the measurement module.

This process may be referred to as initialization of the measurementmodule/carrier. The configured carrier and the measurement module maythen be operable to perform measurement and data acquisition operationsusing the sensor and/or the computer system. In other words, themeasurement module and the programmed carrier unit together may beoperable to perform a measurement device (including a DAQ device),and/or a control device.

In one embodiment, the computer system may also store a programimplementing one or more measurement functions, i.e., a measurementprogram. The measurement program may be a graphical program implementingthe one or more measurement functions. The computer system may beoperable to execute the measurement program to perform the one or moremeasurement functions, preferably in conjunction with operation of thecarrier and/or measurement module, including analysis of data or signalsreceived from the carrier, control of carrier and/or measurement moduleoperations, and user interface functions, among others.

In another embodiment, the computer system may be operable to deploy themeasurement program onto the functional unit of the carrier unit. Inother words, in addition to, or instead of, programming the carrier unitto implement the interface, the computer system may download themeasurement program onto the functional unit of the carrier, after whichthe carrier may be operable to execute the measurement program toperform the one or more measurement functions, preferably in conjunctionwith operation of the measurement module, and possibly the computersystem. The configured carrier and the measurement module may then beoperable to perform measurement and data acquisition operations usingthe sensor and/or the computer system.

In one embodiment, the carrier may also process and/or analyze thesignals, and send the results of the processing or analysis to thecomputer system for storage and/or further analysis.

In various embodiments, the measurement module may also include afunctional unit, e.g., a processor (or microprocessor) and memory, or aprogrammable hardware element (e.g., an FPGA), which may be operable toimplement the module side of the specified interface and/or controlmodule operations. Thus, the measurement module may include measurementcircuitry, e.g., the signal conditioner and/or the signal converter(e.g., ADC or DAC), which may be operable to perform one or more ofsignal conditioning and signal conversion, as well as interfacecircuitry (including the functional unit) which is operable to providean interface for the measurement circuitry. More specifically, thefunctional unit of the measurement module may retrieve the interfaceprotocol information from memory and communicate the interface protocolinformation to the carrier.

In one embodiment, the measurement module may include signal inputterminals for receiving analog inputs, e.g., from a sensor, and foroptionally receiving a Transducer Electronic Data Sheet (TEDS)describing the functionality of the transducer (e.g., sensor) inmachine-readable form. The measurement module may further includeisolation circuitry which may be operable to protect the components ofthe measurement module from spurious signals, signal noise, harmfulvoltage and/or current surges, impedance mismatches, and the like.

The measurement module may also include terminals for communicating withexternal systems such as the computer system, including SPI, triggerline(s), power and ground lines, among others.

In one embodiment, the measurement module may be in the form of ameasurement cartridge and the carrier in the form of a cartridge carrierwhich is operable to receive one or more of the measurement cartridges.For example, the carrier unit may comprise a chassis, a backplanecomprised in the chassis providing for electrical communication, and oneor more slots comprised in the chassis. Each of the one or more slotsmay include a connector that is coupled to the backplane, where each ofthe one or more slots may be adapted for receiving a measurement module.Thus, the carrier may host a plurality of measurement cartridges, eachof which may provide measurement and/or control functionality for ameasurement or control operation or task. The carrier may be operable tocommunicate with each measurement cartridge (i.e., module) and beprogrammed or configured (e.g., by the computer system or by a processoron the carrier) to implement the respective interface of eachmeasurement cartridge. In this manner a suite of sensors may be fielded,each of which feeds signals to a respective measurement cartridge whichin turn communicates through a respective interface (protocol) with thecartridge carrier. The cartridge carrier may in turn couple to acomputer system. Thus, the carrier may support a heterogeneous pluralityof interfaces without having to include a heterogeneous set of interfacehardware components.

In a preferred embodiment, the measurement modules (or cartridges) maybe easily removed, added, and replaced. In other words, measurementmodules may be exchanged to change the configuration or capabilities ofthe measurement system. In one embodiment, the measurement module may bereplaced without powering down the measurement system, i.e., themeasurement module may be “hot-plugged” into the carrier, where themeasurement module may communicate the interface protocol information tothe carrier upon attachment, and the carrier is programmed in response,as described above. In another embodiment, the measurement module and/orcarrier may require a reboot or reset after attachment to perform thedescribed initialization. Thus, the interface circuitry (i.e., themeasurement module) may be operable to communicate the interfaceprotocol to the carrier unit upon one or more of attachment of themeasurement module to the carrier unit, reset of the measurement module,reset of the carrier unit, reboot of the measurement module, and rebootof the carrier unit.

In one embodiment, the carrier may comprise a PXI card, i.e., may beimplemented on a PXI card. The PXI card may be operable to plug into aPXI chassis or a suitably equipped computer system, and may implementthe carrier functionality described above, i.e., the PXI card mayinclude (in addition to PXI interface circuitry, memory, etc.) afunctional unit which is programmable or configurable to implement aninterface based on interface protocol information transmitted from acoupled measurement module, as described above. It should be noted thatother card based implementations besides the PXI card implementation arealso contemplated, for example, PCI, VXI, Infiniband, or other protocolsor platforms may be used to implement a carrier, the PXI card embodimentbeing but one example.

In one embodiment, the carrier unit may comprise or be coupled to aPersonal Digital Assistant (PDA). Thus the PDA may comprise the carrierunit and include one or more slots for measurement modules.Alternatively, the carrier unit may be in the form of an optionallydetachable carrier module, which may in turn couple to a measurementmodule. The measurement module may in turn be operable to couple to asensor or actuator, as described above. In one embodiment, the PDA maybe operable to program the carrier (i.e., the carrier unit's functionalunit) with the interface protocol information provided by themeasurement module, as described in detail above, and may be furtheroperable to provide functionality related to a measurement, and/orcontrol task or operation. In another embodiment, the PDA may be used asan interface to another computer system. For example, a suitablyequipped PDA may provide wireless communication for thecarrier/measurement module.

In one embodiment, the measurement system may include a measurementmodule coupled to a “RIO” Reconfigurable I/O carrier, also referred toas a generalized carrier. As used herein, the term “RIO” carrier refersto a carrier which includes reconfigurable hardware which isconfigurable with respective interface protocols for one or morecartridges. In other words, a RIO carrier with multiple cartridge slotsmay be configured with multiple interfaces for inserted cartridges, suchthat each cartridge's interface is implemented by the RIO carrier. Forexample, if three cartridges with three different respective interfacesare inserted in three slots of the RIO carrier, then the RIO carrier maybe configured to implement the three interfaces. Similarly, if multiplecartridges are sequentially inserted into and removed from a particularslot, the RIO carrier may be configured respectively for each cartridge,i.e., sequentially. The RIO carrier may further be operable to couple toany of various products or platforms.

In one embodiment, a channel or bus may be provided by the RIO carrierfor each cartridge/interface protocol. In other words, each slot mayhave an associated dedicated bus for that slot, with a correspondingportion of the RIO carrier's reconfigurable hardware configurable toimplement the interface for a cartridge inserted into the slot. Inanother embodiment, the RIO carrier may include a shared bus orbackplane common to a plurality of the slots, where inserted cartridgesmay communicate through the common bus or backplane with thereconfigurable hardware of the RIO carrier in accordance with therespective interface protocols implemented on the reconfigurablehardware.

In yet another embodiment, the RIO carrier may be configurable toinclude not only the adaptive interface functionality described above,but may also include or may be configured to include, one or moremeasurement and/or control functions. For example, the carrier mayperform all or a portion of timing, triggering, and synchronizationfunctions for inserted cartridges or modules.

In one embodiment, the RIO carrier may include the carriercomponents/functionality described above, and may also include aregister set, through which communication with the products/platformsmay be effected. In various embodiments, the RIO carrier may provideadditional functions which may include I/O scanning, timing andtriggering, power-on states, logic, digital I/O timing/counting, datatransfer and support for parallel and scanned backplanes, among others.Various products and platforms may provide means for the carrier tocommunicate with external systems. For example, an ApplicationProgramming Interface (API) may allow external systems to read and/orwrite to the registers in the register set to communicate and/or controlthe measurement system. For another example, a processor, e.g., amicro-controller, and a network interface card may couple the registersto a network through which communications with external systems may befacilitated.

In one embodiment, RIO based systems, i.e., a RIO carrier, may beextended with external I/O expansion, i.e., with additional I/Oconnections for coupling to a plurality of measurement modules. A RIOcartridge or card may provide connectors for analog I/O and/or digitalI/O. The digital I/O may be coupled to an I/O expansion device, such asa breakout backplane, which may provide connectivity for a plurality ofmeasurement module cards or cartridges, and may thereby be operable tofacilitate external, synchronized, and conditioned I/O for themeasurement system.

In another embodiment, the RIO card or device may couple to anaddressable backplane, for example, through an SPI with slot selectcapabilities, and which may provide a plurality of individuallyaddressable slots for a plurality of measurement modules or cartridges,which may each be individually targeted for communication by thecarrier. Additionally, the addressable backplane may be expandable,i.e., additional addressable backplanes may be coupled to theaddressable backplane to provide additional slots for additionalmeasurement modules.

In yet another embodiment, the RIO card or device may couple to a“measurement module in the cable”, where a measurement module may becomprised in a cable connector. In other words, the features of ameasurement module, as described above, may be included in one or bothconnectors of a cable which may be coupled to the RIO device or to asensor/actuator, as desired.

Thus, the use of measurement modules in combination with a variety ofplatforms, carrier units, and computer systems provides a broad range ofapproaches for efficient and affordable measurement systems, includingestablished platforms such as PCI/PXI and FieldPoint, generalizedcarriers such as RIO, new USB/Ethernet devices, and small networkedmeasurement nodes (e.g., smart sensors) for highly distributedmeasurement systems. These systems may provide for efficient, low-cost,modular, data acquisition, control, and integrated signal conditioningand conversion, as well as interfaces to sensors and actuators,including plug and play (PnP) sensors, and may do so using a small formfactor.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the present invention can be obtained when thefollowing detailed description of the preferred embodiment is consideredin conjunction with the following drawings, in which:

FIG. 1A illustrates a measurement system, according to one embodiment ofthe invention;

FIG. 1B illustrates a networked measurement system including a servercomputer system, according to one embodiment of the invention;

FIG. 2 is a block diagram of a networked measurement system computersystem, according to one embodiment of the invention;

FIGS. 3A and 3B are block diagrams of two embodiments of a computersystem;

FIGS. 4A and 4B are block diagrams of embodiments of a measurementmodule;

FIGS. 5A and 5B illustrate a measurement module, according to oneembodiment;

FIG. 5C illustrates a hardware layout of a measurement module, accordingto one embodiment of the invention;

FIG. 6 is a block diagram of a carrier with multiple measurementmodules, according to one embodiment of the invention;

FIG. 7A illustrates a cartridge carrier with measurement cartridges,according to one embodiment of the invention;

FIG. 7B illustrates a cartridge carrier with measurement cartridges,according to another embodiment of the invention;

FIGS. 7C and 7D illustrate embodiments of measurement cartridges used inRIO systems;

FIG. 8A is a block diagram of a cartridge carrier in a RIO system withseparate cartridge channels, according to one embodiment;

FIG. 8B is a block diagram of a cartridge carrier in a RIO system with ashared cartridge bus, according to one embodiment;

FIG. 9 is a block diagram of a cartridge carrier, according to oneembodiment;

FIG. 10A is a block diagram of a cartridge controller, according to oneembodiment;

FIGS. 10B and 10C illustrate SPI signal timing, according to oneembodiment;

FIG. 11A is a block diagram of a measurement system usingre-configurable I/O (RIO), according to one embodiment of the invention;

FIG. 11B is a block diagram illustrating functional partitions of a RIOmeasurement system with measurement modules, according to oneembodiment;

FIG. 12A illustrates a PXI carrier card, according to one embodiment ofthe invention;

FIG. 12B illustrates a PDA based measurement system, according to oneembodiment of the invention;

FIG. 12C illustrates various embodiments of a RIO based system with I/Oexpansion;

FIG. 12D illustrates various sensor/measurement systems according to thepresent invention;

FIG. 13 illustrates the use of measurement modules in the context ofcurrent measurement systems;

FIG. 14 is a flowchart of a method for configuring a measurement system,according to one embodiment;

FIG. 15 is a flowchart of another method for configuring a measurementsystem, according to one embodiment;

FIG. 16 is a flowchart of a method for performing a measurementfunction, according to one embodiment;

FIG. 17 is a flowchart of a method for registering a measurementcartridge bitstream with a measurement module interface protocol (MMIP)server;

FIG. 18 is a flowchart of a method for configuring a measurementcartridge;

FIG. 19 illustrates communication layers and interfaces in themeasurement system, according to one embodiment;

FIG. 20 illustrates a high-level architecture of a standard measurementsystem interface, according to one embodiment;

FIGS. 21-30 are timing diagrams for defined methods supported by themeasurement system, according to one embodiment;

FIG. 31 illustrates one embodiment of a measurement module pinoutspecification, according to one embodiment;

FIGS. 32A and 32B illustrate SPI signal timing, according to oneembodiment;

FIGS. 33A-33C are example circuit diagrams for various measurementmodules, according to one embodiment;

FIGS. 33D-33G are example circuit diagrams for various measurementmodule/RIO FPGA configurations, according to one embodiment;

FIGS. 34A-34E illustrate representations of setup information forvarious measurement modules, according to one embodiment;

FIG. 35 is a block diagram for a serial communication block, accordingto one embodiment;

FIG. 36 illustrates a sequence list configuration, according to oneembodiment;

FIG. 37 illustrates an SPI rate description format, according to oneembodiment;

FIG. 38 illustrates a sequence command list file format, according toone embodiment; and

FIG. 39 illustrates one embodiment of a carrier logic configuration forsynchronizing multiple delta-sigma converters.

While the invention is susceptible to various modifications andalternative forms specific embodiments are shown by way of example inthe drawings and may herein be described in detail. It should beunderstood however, that drawings and detailed description thereto arenot intended to limit the invention to the particular form disclosed.But on the contrary the invention is to cover all modifications,equivalents and alternative following within the spirit and scope of thepresent invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE EMBODIMENTS INCORPORATION BY REFERENCE

The following U.S. Patents and patent applications are herebyincorporated by reference in their entirety as though fully andcompletely set forth herein.

U.S. Pat. No. 4,914,568 titled “Graphical System for Modeling a Processand Associated Method,” issued on Apr. 3, 1990.

U.S. Pat. No. 6,219,628 titled “System and Method for Configuring anInstrument to Perform Measurement Functions Utilizing Conversion ofGraphical Programs into Hardware Implementations”.

U.S. Pat. No. 6,173,438 titled “Embedded Graphical Programming System”filed Aug. 18, 1997, whose inventors are Jeffrey L. Kodosky, DarshanShah, Samson DeKey, and Steve Rogers.

U.S. Provisional Patent Application Ser. No. 06/312,254 titled“Measurement System with Modular Measurement Modules That ConveyInterface Information” filed on Aug. 14, 2001, whose inventors are PerrySteger, Garritt W. Foote, David Potter and James J. Truchard.

U.S. patent application Ser. No. 10/194,927 titled “Measurement ModuleInterface Protocol Database and Registration System” filed on Jul. 12,2002, whose inventors are Perry Steger, Garritt W. Foote, David Potterand James J. Truchard.

U.S. patent application Ser. No. 10/194,952 titled “Measurement SystemIncluding a Programmable Hardware Element and Measurement Modules thatConvey Interface Information” filed on Jul. 12, 2002, whose inventorsare Perry Steger, Garritt W. Foote, David Potter and James J. Truchard.

U.S. patent application Ser. No. 09/891,571 titled “System and Methodfor Configuring an Instrument to Perform Measurement Functions UtilizingConversion of Graphical Programs into Hardware Implementations” filed onJun. 25, 2001, whose inventors are Jeffrey L. Kodosky, Hugo Andrade,Brian Keith Odom, Cary Paul Butler, and Kevin L. Schultz.

U.S. patent application Ser. No. 09/745,023 titled “System and Methodfor Programmatically Generating a Graphical Program in Response toProgram Information,” filed Dec. 20, 2000, whose inventors are RamKudukoli, Robert Dye, Paul F. Austin, Lothar Wenzel and Jeffrey L.Kodosky.

U.S. patent application Ser. No. 09/595,003 titled “System and Methodfor Automatically Generating a Graphical Program to Implement aPrototype”, filed Jun. 13, 2000, whose inventors are Nicolas Vazquez,Jeffrey L. Kodosky, Ram Kudukoli, Kevin L. Schultz, Dinesh Nair, andChristophe Caltagirone.

FIGS. 1A and 1B—A Measurement System

FIGS. 1A and 1B illustrate embodiments of a computer system 102 coupledto a measurement or data acquisition (DAQ) device 107. As used herein,the term “measurement device” is intended to include instruments, smartsensors, data acquisition devices or boards, and any of various types ofdevices that are operable to acquire and/or store data. A measurementdevice may also optionally be further operable to analyze or process theacquired or stored data. Examples of a measurement device include aninstrument, such as a computer-based instrument (instrument on a card)an external instrument a data acquisition card, a device external to acomputer that operates similarly to a data acquisition card, a smartsensor, one or more DAQ or measurement modules in a chassis, an imageacquisition device such as an image acquisition board or smart camera, amotion control device and other similar types of devices. Exemplaryinstruments include oscilloscopes, multi-meters, and GPIB, PCI, PXI, andVXI instruments, among others.

In the embodiment of FIG. 1A, the computer system 102 may couple to themeasurement device through a transmission medium, e.g., a serial bus,such as a USB 109. It should be noted that although a USB 109 is shownin this example, any other transmission medium may be used, includingEthernet, wireless media such as IEEE 802.11 (Wireless Ethernet) or(Bluetooth, a network, such as a fieldbus, a Control Area Network (CAN)or the Internet, serial or parallel buses, or other transmission means.For example, in the embodiment of FIG. 1B, the measurement device 107 iscoupled to a server computer system 102 over a network 104, such as theInternet. In one embodiment, the server computer 102 may comprise ameasurement module interface protocol (MMIP) server 102A which isoperable to store a plurality of MMIPs for use by the measurementdevice. The MMIP server may be accessed by the measurement device 107 toretrieve the MMIP, as described in more detail below. In anotherembodiment, the MMIP server may be separate from the computer system102, and the measurement device 107 (or the computer system 102) mayretrieve the MMIP from the server 102A.

Thus, FIGS. 1A and 1B illustrate an exemplary data acquisition ormeasurement system. As FIGS. 1A and 1B show, the measurement device 107may in turn couple to or comprise a sensor or actuator 112, such as apressure or temperature gauge, a thermocouple, an imaging device, (e.g.a camera), or any other type of sensor or actuator. As shown in FIG. 1C,the measurement device 107 may include a measurement module (or multiplemeasurement modules) comprised in a chassis for performing one or moremeasurement (including) or processing functions as described below.

The host computer 102 may comprise a CPU, a display screen, memory, andone or more input devices such as a mouse or keyboard as shown. Thecomputer 102 may operate with the measurement device 107 to analyze ormeasure data from the sensor 112 and/or measurement device 107 or tocontrol the sensor 112 and/or measurement device 107. Alternatively, thecomputer 102 may be used only to configure or program the measurementdevice 107, as described below.

FIG. 2—Block Diagram of a Measurement System

FIG. 2 is a block diagram of a measurement system, according to anotherembodiment of the invention. As FIG. 2 shows, the measurement device 107may comprise a carrier 110 and a measurement module 108. The sensor 112may be coupled to the measurement module 108 which may in turn becoupled to the carrier unit 110, also referred to as carrier 110. Thecarrier 110 may be coupled to computer system 102 via a network (e.g.,the Internet) 104 as shown, or, as mentioned above, may be coupled tothe computer system 102 by other transmission means, including serial orparallel bus, wireless, and CAN, among others. In an embodiment wherethe carrier 110 includes a processor and memory, the carrier may operateindependent of the computer 102, as describe in more detail below.

The measurement module 108 and the carrier 110 together may provide thefunctionality of the measurement device 107 of FIG. 1A. For example, inone embodiment, the measurement module 108 may be operable to performsignal conditioning and/or signal conversion on the signals sent by thesensor 112, and to transmit results of such processing on to the carrier110. In one embodiment, the carrier 110 may be operable to receive datafrom the measurement module 108 and communicate the data (possibly in adifferent format or form) to the computer system 102, e.g., over thetransmission medium 104. For example, the carrier 110 may receive signaldata in a proprietary format from the measurement module 108 and formatthe data for transmission over wireless Ethernet to the computer system102.

In the preferred embodiment, the carrier 110 includes a functional unit106, which may be programmed, for example, by computer system 102 or bya processor/memory comprised in the carrier itself As used herein, theterm “functional unit” may include a processor and memory and/or aprogrammable hardware element. As used herein, the term “processor” isintended to include any of types of processors, CPUs, microcontrollers,or other devices capable of executing software instructions. As usedherein, the term “programmable hardware element” is intended to includevarious types of programmable hardware, reconfigurable hardware,programmable logic, or field-programmable devices (FPDs), such as one ormore FPGAs (Field Programmable Gate Arrays), or one or more PLDs(Programmable Logic Devices), such as one or more Simple PLDs (SPLDs) orone or more Complex PLDs (CPLDs), or other types of programmablehardware. Thus, the carrier unit 110 may be re-configurable, i.e.,programmable by an external computer system, such as computer system102.

More specifically, in the preferred embodiment, the carrier unit 110 maybe operable to receive interface protocol information from themeasurement module 108 specifying how to operate or interface with themeasurement module 108. In one embodiment, the carrier unit 110 may thencommunicate the interface protocol information to the computer system102. Alternatively, measurement module may communicate the interfaceinformation directly to the computer system. Based on the interfaceprotocol information, the computer system 102 may program or configurethe functional unit 106 on the carrier unit 110 to implement theinterface as specified by the measurement module 108. In other words,the measurement module 108 may tell the carrier 110 how to “talk” withit, and the carrier 110 may then tell the computer system 102 how toprogram the carrier 110 to communicate with the measurement module 108accordingly (or the measurement module may tell the computer systemdirectly how to program the camera. The computer system 102 may thenprogram the carrier 110 (i.e., the carrier's functional unit 106),thereby implementing the interface specified in the interface protocolinformation communicated by the measurement module 108.

In another embodiment, the carrier unit 110 may be operable to receivethe interface protocol information from the measurement module 108, anda processor and memory on the carrier unit 110 may then program orconfigure the functional unit on the carrier unit 110 to implement theinterface as specified by the measurement module. In other words, themeasurement module may communicate its interface protocol to thecarrier, and the carrier may program itself (i.e., the processor/memoryon the carrier 110 may program a programmable hardware element on thecarrier 110) to communicate with the measurement module accordingly,thereby implementing the interface specified in the interface protocolinformation communicated by the measurement module.

This process may be referred to as initialization of the measurementmodule/carrier. Further details of this process are described below.

Referring again to FIG. 2, the computer 102 may include a memory mediumon which computer programs according to the present invention may bestored. As used herein, the term “memory medium” includes a non-volatilemedium, e.g., a magnetic media or hard disk, or optical storage; avolatile medium, such as computer system memory, e.g., random accessmemory (RAM) such as DRAM, SRAM, EDO RAM, RAMBUS RAM, DR DRAM, etc.; oran installation medium, such as a CD-ROM or floppy disks, on which thecomputer programs according to the present invention may be stored forloading into the computer system. The term “memory medium” may alsoinclude other types of memory or combinations thereof.

The memory medium may be comprised in the computer 102 where theprograms are executed or may be located on a second computer which iscoupled to the computer 102 through a network, such as a local areanetwork (LAN), a wide area network (WAN), or the Internet. In thisinstance, the second computer operates to provide the programinstructions through the network to the computer 102 for execution.Also, the computer system 102 may take various forms, including apersonal computer system, mainframe computer system, workstation,network appliance, Internet appliance, personal digital assistant (PDA),television set-top box, instrument, or other device. In general, theterm “computer system” can be broadly defined to encompass any devicehaving at least one processor which executes instructions from a memorymedium.

Thus, in various embodiments, software programs of the present inventionmay be stored in a memory medium of the respective computer 102, or in amemory medium of another computer, and executed by the CPU. The CPUexecuting code and data from the memory medium thus comprises a meansfor receiving interface protocol information and programming orconfiguring the carrier 110 to implement the specified interface, asdescribed in more detail below.

In one embodiment, the computer system 102 may also store a programimplementing one or more measurement functions, i.e., a measurementprogram, e.g., a software program, such as a graphical program,implementing the one or more measurement functions. The term“measurement function” may include measurement, data acquisition, and/orcontrol functions, such as displaying received data, analyzing and/orprocessing received data to generate a result, performing signalprocessing on received data, or otherwise analyzing and/or processingreceived data to perform a measurement. Examples of measurementfunctions include various instrumentation functions or controlfunctions.

In the present application, the term “graphical program” or “blockdiagram” is intended to include a program comprising graphical code,e.g., two or more nodes or icons interconnected in one or more of a dataflow, control flow, or execution flow format, where the interconnectednodes or icons may visually indicates the functionality of the program.Thus the terms “graphical program” or “block diagram” are each intendedto include a program comprising a plurality of interconnected nodes oricons which visually indicates the functionality of the program. Agraphical program may comprise a block diagram and may also include auser interface portion or front panel portion. The user interfaceportion may be contained in the block diagram or may be contained in oneor more separate panels or windows. A graphical program may be createdusing any of various types of systems which are used to develop orcreate graphical code or graphical programs, including LabVIEW, DASYLab,and DiaDem from National Instruments, Visual Designer from IntelligentInstrumentation, Agilent VEE (Visual Engineering Environment),Snap-Master by HEM Data Corporation, SoftWIRE from MeasurementComputing, ObjectBench by SES (Scientific and Engineering Software),Simulink from the MathWorks, WiT from Coreco, Vision Program Managerfrom PPT Vision, Hypersignal, VisiDAQ, VisSim, and Khoros, among others.In the preferred embodiment, the system uses the LabVIEW graphicalprogramming system available from National Instruments.

The computer system 102 may be operable to execute the measurementprogram to perform the one or more measurement functions, preferably inconjunction with operation of the carrier 110 and/or measurement module108. For example, the measurement program may be executable to performone or more of measurement or control functions, including analysis ofdata or signals received from the carrier, control of carrier and/ormeasurement module operations, user interface functions, imageprocessing or machine vision functions, and motion control functions,among others.

In another embodiment, the computer system may be operable to deploy themeasurement program onto the functional unit 106 of the carrier unit110. In other words, in addition to, or instead of, programming thecarrier unit 110 to implement the interface, the computer system maydownload the measurement program onto the functional unit of thecarrier. After deploying a software program on the functional unit 106the carrier 110 may be operable to execute the measurement program toperform the one or more measurement functions, preferably in conjunctionwith operation of the measurement module 108, and possibly the computersystem 102.

The configured carrier 110 and the measurement module 108 may then beoperable to perform measurement operations using the sensor 112 and/orthe computer system 102.

FIGS. 3A and 3B—Computer Block Diagrams

FIGS. 3A and 3B are exemplary block diagrams of the computer 102 ofFIGS. 1A and 1B, respectively. The elements of a computer not necessaryto understand the operation of the present invention have been omittedfor simplicity. The computer 102 may include at least one centralprocessing unit (CPU) or processor 160 which is coupled to a processoror host bus 162. The CPU 160 may be any of various types, including anx86 processor, a PowerPC processor, a CPU from the Motorola family ofprocessors, a CPU from the SPARC family of RISC processors, as well asothers. Main memory 166 may be coupled to the host bus 162 by means ofmemory controller 164. The main memory 166 is operable to store one ormore programs according to the present invention. For example, thememory medium 164 may store a program which is executable to useinterface protocol information received from, the carrier 110 to programor configure the functional unit 106 comprised in the carrier 110. Themain memory 166 may also store operating system software, i.e., softwarefor operation of the computer system, as well as one or more applicationprograms, as is well known to those skilled in the art. In addition, themain memory 166 may store one or more measurement programs which areexecutable to perform DAQ, measurement, and/or control tasks.

The host bus 162 is coupled to an expansion or input/output bus 170 bymeans of a bus controller 168 or bus bridge logic. The expansion bus 170is preferably the PCI (Peripheral Component Interconnect) expansion bus,although other bus types may be used. The expansion bus 170 may includeslots for various devices, the examples shown including a controller186, e.g., a USB controller 186, shown in FIG. 3A coupled to the carrier110 (as also shown in FIG. 1A), and a network controller 184 shown inFIG. 3B coupling to the carrier 110 over a network, as described abovewith reference to FIG. 1B. In both embodiments shown, the carrier 110 iscoupled to a measurement module 108 (or multiple measurement modules),which may itself be coupled to a sensor 112 as shown.

The computer 102 may further comprise a video display subsystem 180 andhard drive 182 coupled to the expansion bus 170, also shown. It shouldbe noted that the network controller 184 may be any type of networkcontroller, including Ethernet, wireless Ethernet, Bluetooth, and CAN,among others. Furthermore, the USB controller shown is meant to beillustrative only, i.e., any other type of controller may be used asdesired to communicate with the carrier 110. In other embodiments, thecontroller 186 may be comprised in the bus controller 168, or may beimplemented in any other forms customary and known in the art. Ofcourse, the embodiments shown in FIGS. 3A and 3B may be combined invarious ways, such as, for example, coupling to a first carrier througha controller, and coupling to a second carrier via a network.

FIGS. 4A and 4B—Measurement Modules with a Functional Unit

FIGS. 4A and 4B are block diagrams of embodiments of a measurementmodule 108 where the measurement module 108 includes one or morefunctional units 106. As mentioned above, a functional unit refers toeither a processor 306 and memory (or multiple processors and/ormemories) or one or more programmable hardware elements 308, such as anFPGA, or various combinations thereof.

FIG. 4A—A Measurement Module with Processor

FIG. 4A is a block diagram of a measurement module 108A including aprocessor 306, e.g., a micro-controller. As FIG. 4A shows, themeasurement module 108A may include measurement circuitry which isoperable to perform one or more of signal conditioning and signalconversion. For example, in one embodiment, the measurement circuitrymay include a signal conditioner 302 and/or a signal converter 304, suchas an analog to digital converter (ADC) 304, as shown. In otherembodiments, the signal converter 304 may comprise a digital to analogconverter, or other types of signal converter, as desired.

The measurement module 108A may also include interface circuitry whichis operable to provide an interface for the measurement circuitry. Inone embodiment, the interface circuitry may be operable to couple to acarrier unit 110, and may also be operable to communicate an interfaceprotocol to the carrier unit 110 describing the interface.

In the embodiment shown in FIG. 4A, the interface circuitry includesmicro-controller 306 and memory 307, such as an EEPROM 307, containing aDAQ Electronic Data Sheet (EDS), defined by IEEE 1451.2, and an optionalcalibration history.

IEEE 1451.2 defines an interface between transducers and microprocessorsuseful in industrial automation and other fields. The standard defines aphysical interface comprising a data transport serial link, in additionto triggering, interrupt and hot swap signaling. The standard alsodefines a transducer electronic data sheet, TEDS, that describes thefunctionality of the transducer in machine-readable form. The interfacesupports as many as 255 independent transducer channels. These may beaccessed individually or as a unit. The standard may be used toimplement a variety of measurement functions.

In one embodiment, the memory storing the DAQ-EDS 307 may also storeprogram instructions for the processor 306. In another embodiment, themeasurement module 108A may include additional memory, not shown, forstoring the program instructions. The program instructions may beexecutable by the processor 306 to implement the measurement module sideof the interface and/or to manage operations of the measurement module108A. In another embodiment, the program instructions may be executableby the processor 306 to perform a measurement task or operation.

In one embodiment, as described above, the carrier unit 110 may includethe functional unit 106, such as micro-controller or FPGA which isprogrammable to interface with the measurement module in accordance withthe communicated interface protocol. In other words, the carrier unit110 may comprise an adaptive interface which uses the functional unit106 to implement an interface according to instructions orspecifications from the measurement module 108. The measurement module108 and the programmed carrier unit 110 together may then be operable toperform as one or more of a measurement device and a control device.

As described above, in one embodiment, the carrier unit 110 may beoperable to couple to a computer system, i.e., computer system 102,which is operable to program the one or more functional units tointerface with the measurement module in accordance with thecommunicated interface protocol. In other words, the computer system 102may retrieve or receive the interface protocol information from thecarrier, or from the measurement module 108A and program the carrier110, i.e., the functional unit(s) 106 on the carrier unit 110, therebyimplementing the interface protocol for communication with and operationof the measurement module 108A. As mentioned above, in one embodiment,the computer system 102 may be operable to couple to the carrier unit110 over a network, such as the Internet, thus the carrier unit 110 maybe programmed remotely by the computer system 102. As also mentionedabove, in one embodiment, the computer system may comprise a PersonalDigital Assistant (PDA), as described below, or any other type ofcomputing device.

In another embodiment, the computer system 102 may be comprised in thecarrier unit. For example, the computer may be a “computer-on-a-card” or“computer-on-a-chip”, where substantially all of the functionality of aPC (personal computer) is provided by components on a computer card,board or chip contained in the carrier unit 110. In this embodiment, themodule 108 may communicate the interface protocol to the carrier 110,and a processor/memory on the carrier 110 may program the functionalunit on the carrier 110 with the interface protocol.

The measurement module 108, as described above, may be further operableto couple to a sensor 112. The sensor 112 may send sensor signals to themeasurement module for one or more of signal conditioning and signalconversion. For example, the sensor 112 may measure a phenomenon, suchas temperature, pressure, voltage, current, or any other phenomenon, andsend signals to the measurement module, as indicated by the analog input310 of FIG. 4A. The signal conditioner 302 may then perform signalconditioning on the signals, where signal conditioning may include oneor more of protection, isolation, filtering, amplification, andexcitation, or other signal conditioning operations.

The conditioned signals may then be processed by the signal converter304, which may be operable to perform one or more of analog to digital(A/D) conversion and digital to analog (D/A) conversion. In thisembodiment, the input is analog (310), therefore the signal converter304 is an ADC 304, as shown.

The conditioned converted signals may then be transmitted by theinterface circuitry to the carrier 110 using the specified interfaceprotocol. In other words, the processor 306 may transmit theconditioned, converted signals to the carrier 110 over the serialtransmission medium SPI 316. The carrier 110 may then transmit thesignals to an external system, such as computer system 102.

In one embodiment, the carrier 110 may process and/or analyze thesignals, and send the results of the processing or analysis to thecomputer system 102 for storage and/or further analysis. In anotherembodiment, the carrier 110 may send a control signal to a component ofthe measurement system or to an external system in response to theanalysis.

As FIG. 4A also shows, the measurement module 108A may also includeadditional transmission lines and/or buses for operation, e.g., atrigger line 314 coupled to the ADC 304 which may receive triggersignals from an external source, such as computer system 102, and apower line 312 for supplying power to the measurement module.

FIG. 4B—A Measurement Module with Programmable Hardware

FIG. 4B is a block diagram of a measurement module 108B including aprogrammable hardware element 308, e.g., an FPGA 308. As may be seen,measurement module 108B is substantially the same as measurement module108A described above with reference to FIG. 4A, but where the processor306 is replaced with programmable hardware element 308, thereforedescription of the unchanged components is abbreviated or omitted.

As FIG. 4B shows, the measurement module 108B may include measurementcircuitry, e.g., the signal conditioner 302 and/or the signal converter304 (e.g., ADC or DAC), which may be operable to perform one or more ofsignal conditioning and signal conversion, as well as interfacecircuitry which is operable to provide an interface for the measurementcircuitry. As described above, the interface circuitry may be operableto couple to a carrier unit 110, and to communicate an interfaceprotocol to the carrier unit 110 describing the interface, whereupon thecarrier unit's one or more functional units may be programmed (bycomputer system 102 or by a processor/memory on the carrier 110) usingthe interface protocol to implement the interface. After beingprogrammed or configured with the interface, the measurement module andthe programmed carrier unit together may then be operable to perform asone or more of a DAQ device, a measurement device, and a control device.

More specifically, in one embodiment, the programmable hardware elementof the measurement module 108, e.g., the FPGA 308, may retrieve theinterface protocol information from memory, as represented by theDAQ-EDS 307, and communicate the interface protocol information to thecarrier 110. In one embodiment, the memory storing the DAQ-EDS 307 mayalso store configuration information, e.g., a hardware description, forthe FPGA 308. In another embodiment, the measurement module 108B mayinclude additional memory, such as non-volatile memory, not shown, forstoring the configuration information. The configuration information maybe usable to configure or program the FPGA 308 to implement themeasurement module side of the interface and/or to manage operations ofthe measurement module 108B.

In one embodiment, a hardware netlist (preferably an FPGA-specificnetlist) may be generated from the hardware description using varioussynthesis tools. The term “netlist” comprises various intermediatehardware-specific description formats comprising information regardingthe particular hardware elements required to implement a hardware designand the relationship among those elements. The hardware netlist is usedto create or configure the programmable hardware element to execute thespecified function. As used herein, the term “hardware configurationfile” refers to the program, bitfile, etc., which is loaded onto theprogrammable hardware element.

As also described above, the measurement module 108B may be operable tocouple to sensor 112 which may send sensor signals to the measurementmodule for signal conditioning and/or signal conversion. Theconditioned, converted signals may then be transmitted by the interfacecircuitry to the carrier 110 using the specified interface protocol. Inother words, the FPGA 308 may operate to transmit the conditioned,converted signals to the carrier 110 over the serial transmission mediumSPI 316. The carrier 110 may then transmit the signals (possibly in adifferent format) to an external system, such as computer system 102.

Thus, in one embodiment, the measurement module may communicateinterface information to the carrier unit, where the interfaceinformation specifies an interface for operating with the measurementmodule; the carrier unit 110 may communicate the interface informationto the computer system 110; (alternatively, the measurement module 108may communicate interface information directly to the computer system102) and the computer system 102 may program a functional unit on thecarrier unit 110, thereby implementing the specified interface in thecarrier unit. In another embodiment, the carrier unit 110 may include aprocessor and memory which receives the interface information from themeasurement module, and programs the functional unit on the carrier unit110 to implement the interface.

After the programming, the carrier unit 110 and the measurement module108 may together be operable to perform one or more of a measurement andcontrol task. In one embodiment, after the carrier unit 110 isprogrammed, the carrier unit 110 and the measurement module 108 togetherperform one or more of a data acquisition, measurement, and controltask. In another embodiment, the computer system 102 may also performone or more of a measurement and control task in conjunction with thecarrier unit 110 and the measurement module 108.

Various embodiments of the invention may include additional features toprovide efficient, low-cost measurement solutions. For example,DAQ-on-a-chip components and inexpensive, low-power digital componentssuch as networking, processors, AID converters, etc., allow measurementmodules 108 to be developed which provide a variety of signalconditioning/conversion functions in a small form at a modest price.Additionally, various embodiments of the invention address the currenttrend toward networked/digital sensors and the emergence of plug andplay (PnP) (analog) sensors, in that the carrier 110 is capable ofadaptive “hot plug” functionality, i.e., the carrier 110 may adaptitself automatically to interface correctly with a smart sensor (i.e., asensor/measurement module device). Thus, in various embodiments of theinvention, the customer may be provided with modularity and flexibility,easy sensor connection (with integrated signal conditioning/conversion),and a variety of network options in that there is no dominant standardwhich requires compliance. Additionally, the customer may be provided anaffordable and feasible path to smart sensors.

FIGS. 5A and 5B—Measurement Module

FIGS. 5A and 5B illustrate a measurement module, according to oneembodiment. More specifically, FIGS. 5A and 5B illustrate a measurementmodule 108 in the form of a measurement cartridge which may be insertedinto a slot in a cartridge carrier, as shown in FIGS. 7A and 7B,described below.

As FIG. 5A shows, the cartridge 108 may include signal input terminals301 which may provide direct connectivity to various sensors anddevices. In one embodiment, the measurement cartridge 108 may includeintegrated conditioning and isolation logic 306, including logic forsignal conditioning 302, signal conversion (e.g., A/D and/or D/Aconverters) 304, and/or isolation 305, as shown. In various embodiments,the logic may be implemented in hard-wired circuitry, programmablehardware, such as an FPGA, and/or a micro-controller/memory, as desired.Finally, in the embodiment shown, the cartridge 108 may include a RIO(Reconfigurable I/O) interface 303 for communicating with a RIO carrier,as described in more detail below. In this embodiment, all timing,triggering, synchronization, etc., may be relegated to the RIO carrier,thereby simplifying the functional requirements of the measurementcartridge 108. The cartridge interface may comprise a very simpleinterface, e.g., SPI or 8 parallel DIO, through which communication witha RIO carrier may be facilitated.

FIG. 5B illustrates the measurement cartridge of FIG. 5B, where thecartridge 108 is shown with a cartridge housing 309. The housing 309 mayserve to protect the various cartridge components and to providestructural support to the cartridge 108. In a preferred embodiment, themeasurement cartridge may have a compact form factor. For example, inone embodiment, the measurement cartridge may measurement approximately3.4″ H×2.5″ D×0.8″ W, although other compact form factors are alsocontemplated.

In one embodiment, the measurement cartridge 108 may be operable toprovide single-point and waveform I/O, e.g., analog: under 1 MS/s percartridge, and/or digital: paralleled pass-through (fast). In a typicalembodiment, channel granularity for the cartridge 108 may include 4channels/module (higher with mass termination) for analog I/O, and/or 8parallel I/O lines pass-through (higher density with mass termination)for digital I/O. Additionally, in one embodiment, up to 500 mW of powerper slot on the cartridge carrier 110 may be provided for the operationof the cartridge 108.

FIG. 5C—Measurement Module Hardware Layout

FIG. 5C illustrates one embodiment of a hardware layout of themeasurement module 108. Note that FIG. 5C only illustrates thefunctional components of the module, and that in the preferredembodiment, a housing or chassis may be included for enclosure,protection, or support of the module components, as illustrated in FIGS.5A and 5B, and FIG. 7B, described below.

As FIG. 5C shows, in one embodiment, a printed wiring board (PWB) may beequipped with signal input terminals 301 for receiving analog inputs310, e.g., from a sensor 112. In one embodiment, a subset of the inputterminals 301 may be used to receive an optional Transducer ElectronicData Sheet (TEDS) describing the functionality of the transducer (e.g.,sensor 112) in machine-readable form.

The PWB of the measurement module 108 may further include signalconditioning logic or circuitry 302, such as signal conditioners, MUXs,etc., which may be operable to receive the signals from the analoginputs 310 and perform signal conditioning on the signals, as is wellknown in the art.

As FIG. 5C also shows, the PWB may also include signal conversion logicor circuitry 304, such as the ADC shown, which may be operable toreceive the conditioned signals from the signal conditioning circuitry302 and perform any of various signal conversion operations on thesignals. In the embodiment shown, the ADC 304 may operate to convert theconditioned analog signals to digital signals. Of course, in otherembodiments, other signal conversions may be performed as desired,including digital to analog, or any other signal conversion.

As indicated above, in one embodiment, the PWB may include a functionalunit 106, such as a processor/memory 306 and/or a programmable hardwareelement, such as an FPGA 308. As described above, the functional unit106 may operate to provide an interface between the signalconditioning/conversion components 302/304 and external systems, such ascomputer system 102. As also mentioned above, the functional unit 106may be operable to communicate interface protocol information to acarrier 110 indicating how to communicate with and operate themeasurement module 108.

In one embodiment, isolation circuitry 305 may also be included on thePWB which may be operable to protect the components of the measurementmodule from spurious signals, signal noise, harmful voltage and/orcurrent surges, impedance mismatches, and the like.

As FIG. 5C also shows, the PWB may also include terminals forcommunicating with external systems such as the computer system 102,including SPI 316, trigger line(s) 314, power 312 and ground 318 lines,among others.

In one embodiment, the measurement module 108 may comprise a cartridge,e.g., a measurement cartridge, which may be operable to be inserted intoa slot in a chassis, described in detail below.

One benefit of the measurement module design presented above relates tocost. For example, in one embodiment of the measurement module 108, thecost may be estimated in the following way (in U.S. dollars circa 2001):

Basic System: PWB:  $4.50 Screw Terminals:  $4.00 Enclosure/label: $1.10 Manufacturing: $10.00 Total (w/o isolation) $19.60 Isolation:$12.50 Total (w/ isolation) $32.10 Feature Circuitry: Micro-Processor: $5.00 Signal Conditioner, MUX:  $5.00-10.00 ADC System:  $7.00-10.00Total (w/ isolation) $49.10-57.10Thus, for less than $60, the measurement module described above may bemanufactured, resulting in a versatile and affordable DAQ/measurementsolution. Other examples of estimated costs for measurement cartridgesare given below:

Estimated Cost to Builds Cartridge Non-Iso Isolated Slow 4-ch AI $42.60$55.10 16-bit ADC, 0-1 V, 0-10 V Fast 4-ch AI 36.60 49.10 12-bit ADC, 50kS/s 4-ch T/C 39.60 53.10 16-bit ADC, +−1 deg C. 4-ch AO 50.60 63.1012-bit DAC, 0-10 V 3-ch RTD 3-wire, 16-bit ADC 41.60 54.10 8-ch DI (5-30VDC) 25.60 38.10 8-ch DO (5-30 VDC) 29.10 41.60Examples of estimated costs for simple network adapters/carriers—CTB:

Estimated Cost to Builds 4-SLOT 1-SLOT Serial RS-232 $71 $61 SerialRS-485, isolated  80  70 Simple USB  66  56 Simple Ethernet  80  70Ethernet w/ 32-bit uproc 150 140FIG. 6—Multiple Measurement Modules with Carrier

FIG. 6 is a block diagram of a measurement system comprising a carrier110 and a plurality of measurement modules 108, according to oneembodiment. As FIG. 6 shows, the plurality of measurement modules 108may include analog input module 108C, analog output module 108D, anddigital I/O module 108E, as well as other measurement modules not shown.Thus, the carrier 110 may be operable to communicate with eachmeasurement module 108 and be programmed or configured (e.g., by acomputer system 102 or by a processor/memory on the carrier 110) toimplement the respective interface of each measurement module. In thismanner a suite of sensors 112 may be fielded, each of which feedssignals to a respective measurement module 108 which in turncommunicates through a respective interface (protocol) with the carrier110. Thus, the carrier 110 may support a heterogeneous plurality ofinterfaces without having to include a heterogeneous set of interfacehardware components.

It should be noted that in various embodiments, the carrier 110 may alsobe operable to perform other functions in addition to the adaptiveinterface functionality described above. For example, in one embodiment,the carrier may include network control circuitry (or have a functionalunit configured to perform network control functions), and thus maycomprise a networked measurement and control device, or a networked dataacquisition device. In other words, the carrier unit may comprise one ormore of an Ethernet carrier, a USB carrier, and a wireless carrier,among others, to facilitate transmission of data over a network toexternal systems, e.g., the computer system 102.

In one embodiment, the carrier 110 may include an IP address and webserver capabilities. Thus the carrier unit may be able to publishreceived signals or measurement data over the Internet. The carrier 110may similarly be operable to receive signal data over the Internet forprocessing. In another embodiment, one or more measurement cartridges108 coupled to the carrier 110 may have an IP address and web servercapabilities, and thus may be able to communicate with remote systemsover the Internet, for example, to stream sensor data (e.g., numericaldata or images) to a website for access by other systems or users.

In one embodiment, the carrier 110 may include a module 108 comprising acomputer on a card, i.e., the functions of the computer system 102 maybe performed by a module comprised in a slot on the carrier 110.

In one embodiment, the carrier unit 110 may comprise a measurement andcontrol system, such as an industrial programmable logic controller, andmay include one or more of a real time controller and an embeddedcontroller.

In another embodiment, the measurement and control system may be usablein a PC based measurement and control system, and example of which isillustrated in FIG. 1A. For example, the carrier 110 may comprise or beoperable to couple to a PC, i.e., computer system 102, and may beoperable to perform measurement and control functions using the PC'sprocessor 160 and memory 166. In one embodiment, the PC basedmeasurement and control system may comprise one or more of a real timecontroller and an embedded controller. In another embodiment, the PCbased measurement and control system may comprise one or more of a PCIcarrier and a PXI carrier. In another embodiment, the carrier itself maycomprise one or more of the PCI carrier and the PXI carrier.

In yet another embodiment, the carrier may comprise a DAQ-in-cable,e.g., used in a PC based DAQ or measurement system. In other words, thecarrier 110 may be comprised in a cable connector, where one end of thecable is operable to be connected to the computer system 102, or to anetwork device, and the other end is operable to be connected to ameasurement module. Thus, the cable itself may operate to performvarious DAQ and/or measurement or analysis functions. Other embodimentsof the carrier 110 are described below with reference to FIGS. 7A-13.

As FIG. 6 shows, the carrier 110 may receive signals from themeasurement modules 108, optionally process the signals, and send thesignals (or results) on to other systems and/or components of themeasurement system. For example, as indicated by FIG. 6, the carrier 110may transmit the signals to one or more of a Pass-through SPI+, e.g., abreakout/cable to FPGA board; a board bus (PXI, PC-104, etc.);Bluebus/FieldPoint adapter; a Network adapter, such as Ethernet, USB,CAN, or RS-232/485, among others; a wireless adapter, such as 802.11B orBluetooth; a Handheld/PDA adapter, for example, Springboard, cradle,etc.; and a smart sensor module, among others.

FIGS. 7A and 7B—Measurement Cartridges With Cartridge Carrier

FIGS. 7A and 7B illustrate embodiments of the invention where themeasurement module 108F is in the form of a measurement cartridge andthe carrier 110 is in the form of a cartridge carrier 110A which isoperable to receive one or more of the measurement cartridges 108F. FIG.7A illustrates an embodiment in which the cartridge comprises a cardwith no housing, whereas FIG. 7B illustrates an embodiment in which thecartridge includes a housing, as shown.

In one embodiment, the carrier unit 110A may comprise a chassis, abackplane comprised in the chassis providing for electricalcommunication, a functional unit and one or more slots comprised in thechassis. Each of the one or more slots may include a connector that iscoupled to the backplane, where each of the one or more slots may beadapted for receiving one of the measurement modules 108F. Thus, thecarrier 110 may host a plurality of measurement cartridges 108F, each ofwhich may provide measurement and/or control functionality for ameasurement or control operation or task. As mentioned above withreference to FIG. 6, the carrier 110A may be operable to communicatewith each measurement cartridge (i.e., module) 108F and be programmed orconfigured (e.g., by a computer system 102 or by a processor/memory onthe carrier 110) to implement the respective interface of eachmeasurement cartridge. In this manner a suite of sensors 112 may befielded, each of which feeds signals to a respective measurementcartridge 108F which in turn communicates through a respective interface(protocol) with the cartridge carrier 110A. Thus, the carrier 110A maysupport a heterogeneous plurality of interfaces without having toinclude a heterogeneous set of interface hardware components. In oneembodiment, a channel or bus may be provided by the carrier 110 for eachcartridge/interface protocol. In other words, each slot may have anassociated dedicated bus for that slot, with a corresponding portion ofthe carrier's reconfigurable hardware configurable to implement theinterface for a cartridge inserted into the slot. In another embodiment,the carrier 110 may include a shared bus or backplane common to aplurality of the slots, where inserted cartridges may communicatethrough the common bus or backplane with the reconfigurable hardware ofthe carrier 110 in accordance with the respective interface protocolsimplemented on the reconfigurable hardware.

In a preferred embodiment, the measurement modules 108 (or cartridges)may be easily removed, added, and replaced. In other words, measurementmodules may be exchanged to change the configuration or capabilities ofthe measurement system. In one embodiment, the measurement module 108may be replaced without powering down the measurement system, i.e., themeasurement module 108 may be “hot-plugged” into the carrier 110, where,during operation of the measurement system, the measurement module 108may communicate the interface protocol information to the carrier 110upon attachment, and the carrier 110 is programmed in response, asdescribed above. In another embodiment, the measurement module 108and/or carrier 110 may require a reboot or reset after attachment toperform the described initialization.

For example, during operation of the measurement system, a newmeasurement module 108 (or cartridge) may be added (i.e., inserted orattached) to the carrier 110. The measurement system may automaticallyperform the initialization described above with respect to the addedmeasurement module 108. In other words, during operation of themeasurement system, the newly coupled measurement module 108 maycommunicate respective interface information to the carrier 110, whichmay then be programmed (e.g., by the computer system 102 or by aprocessor/memory on the carrier 110) to implement the respectiveinterface, thereby enabling operations with the new measurement module108. In one embodiment, the new measurement module 108 may replaceanother measurement module which was removed during operation of themeasurement system.

Thus, the interface circuitry (i.e., the measurement module 108) beingoperable to communicate the interface protocol to the carrier unit 110describing the interface may comprise the interface circuitry beingoperable to communicate the interface protocol to the carrier unit 110upon one or more of attachment of the measurement module to the carrierunit, reset of the measurement module, reset of the carrier unit, rebootof the measurement module, and reboot of the carrier unit.

As FIGS. 5C, 7A, and 7B show, in a preferred embodiment, the measurementmodule 108 may have a small form factor. For example, in one embodiment,the measurement module 108 may have dimensions less than or equal toapproximately 1 inch by 2 inches by 3 inches. In one embodiment, themeasurement module may have dimensions of approximately 0.2 inches by 1inch by 1 inch or more. In yet another embodiment, the measurementmodule may have dimensions of approximately 0.8 inches by 2.5 inches by3.4 inches or more. Thus, in a preferred embodiment, the measurementmodule 108 has a compact form factor which may enable deployment in avariety of devices or carriers with minimal space requirements.

Thus, in one embodiment, the measurement module 108 may comprise ameasurement cartridge including signal conditioning, ADC,microprocessor, and optional isolation, for sensor to digitaloperations. Additionally, the cartridge may provide an SPI digitalinterface with simple protocol, and EDS/calibration history on board. Ina preferred embodiment, the cartridges may have low channel counts,e.g., 4-channel analog, 8-channel digital.

The cartridge carriers are preferably able to convert SPI to standardbus/network signals, and implement power-on states, plug and play, andwatchdogs. Additionally, the cartridge carriers may be provided withapplication-specific form factors and functions. In other words, thecartridge carriers may be developed specifically to match the customersspace and function needs. Example carriers 110 may include, but are notlimited to, 4-slot Ethernet carrier, 4-slot and 1-slot USB carrier,multi-slot RIO carrier, 1-slot wireless carrier, and CAN carrier, amongothers.

Thus, in various embodiments, the measurement modules or cartridges mayprovide any or all of low first channel cost, low power requirements,small size, “good” DAQ performance (for example, ˜50 kS/s 12-bit to10S/s 20-bit), integrated signal conditioning, optional isolation,support for plug and play sensors (IEEE 1451.4), and easy use andconfiguration. Additionally, the measurement modules/cartridges may berugged, i.e., may be suitable for industrial use. In variousembodiments, the cartridges may plug into one or more of an Ethernetcarrier, a USB carrier, an Ethernet Vision I/O slot, a PXI carrier, aPCI carrier, handhelds, DAQ in the cable, and RIO devices (e.g.,panelettes), among others. Example functions contemplated formeasurement cartridges include, but are not limited to, thermocouples,analog (e.g., 10 V) inputs, fast Al/vibration, analog output (e.g., 1Vto 10V), digital input (e.g., 5V to 30V), and digital output (e.g., 5Vto 30V).

Re-Configurable I/O Systems

In one embodiment, the measurement system may include a measurementmodule coupled to a “RIO” Reconfigurable I/O carrier 110D, also referredto as a generalized carrier 110D. As used herein, the term “RIO” carrierrefers to a carrier which includes reconfigurable hardware, e.g., anFPGA, which is configurable with respective interface protocols for oneor more cartridges. In other words, a RIO carrier 110D with multiplecartridge slots may be configured with multiple interfaces for insertedcartridges, such that each cartridge's interface is implemented by theRIO carrier 110D.

In yet another embodiment, the RIO carrier 110D may be configurable toinclude not only the adaptive interface functionality described above,but may also include or may be configured to include, one or moremeasurement and/or control functions. For example, the carrier mayperform all or a portion of timing, triggering, and synchronizationfunctions for inserted cartridges or modules. Further descriptions ofRIO based embodiments of the invention are presented below withreference to FIGS. 7C-7D and FIGS. 8A-11, described below.

FIGS. 7C and 7D—Measurement Cartridges in RIO Systems

FIGS. 7C and 7D illustrates two embodiments of measurement systems usingmeasurement modules with RIO carriers 110. FIG. 7C illustrates anembodiment in which the measurement module (or cartridge) 108 is coupledto a stand-alone chassis with RIO 110E, which may function as the RIOcarrier 110 for the system. In other words, the chassis 110E includes aRIO functional unit 308, e.g., on or coupled to the chassis backplane,for implementing the interface protocol of the measurement cartridge108, and/or for providing other RIO functionality. Additionally, in thisembodiment, a controller cartridge or module 702 may be coupled to orinserted into the chassis 110E, and may provide one or more of a powersupply, communications (e.g., Ethernet, USB, 1394, etc.), real timeapplication software, such as LabVIEW/RT from National Instruments,executable by an on-board processor and memory (comprised on thecontroller 702), and a PCI bus to RIO. The controller 702 may thusprovide some or all of the functionality which might normally beprovided by a host computer 102, as described above, thereby allowingthe system as shown to operate without the host computer 102. In otherwords, in one embodiment, the controller 702 may function as the hostcomputer system 102.

FIG. 7D illustrates another embodiment of a RIO-based measurementsystem, in which the RIO functionality (e.g., the RIO FPGA 308) isprovided by an R Series board 110F which is coupled to a simple breakoutfor R Series 720 by a transmission medium, e.g., a 68 pin cable 703, asshown. The breakout 720 is also operable to receive the measurementcartridge 108, and so may function as a cartridge chassis. In onembodiment, the R Series board, in addition to the RIO FPGA 308, mayinclude a processor and memory, and thus may provide the functionalityof a host computer 102, e.g., storing and executing applicationsoftware, programming the RIO FPGA with the module interface protocol,etc. In another embodiment, the breakout 720 may couple to an externalcomputer system 102, e.g., via a transmission medium. In yet anotherembodiment, a computer-on-a-card, may be inserted into the chassis 720,and may serve as the host computer 102, as described above.

Thus, in some embodiments, the carrier 110 may include a processor andmemory which may provide some or all of the functionality of the hostcomputer system 102, described above. The processor and memory of thecarrier 110 may be operable to store and execute real time applicationsoftware, such as LabVIEW/RT.

For example, in one embodiment, the carrier 110 may comprise a C-Seriesplatform (e.g., from National Instruments), which may support a varietyof multi-slot chassis, e.g., a 16-slot chassis, an 8-slot chassis, a4-slot chassis, among others, and may facilitate high-speed real timecontrol (e.g., 10× to 100× loop performance versus PLCs). The carriermay include a 1-slot multi-drop bus adapter. The platform may alsoinclude a stand-alone x86 controller module with LabVIEW/RT. In oneembodiment, the carrier 110 may be DIN-rail and panel mounted.Additionally, the carrier may be configured with a RIO personality, suchas, for example, a personality for synchronous single-point acquisition.In one embodiment, the carrier 110 may support an option to distributeindividual cartridges through one-slot deterministic bus adapters. Thisand similar embodiments of the inventions may be suitable for suchapplications as fast machine control, embedded systems, distributedmonitoring, hardware-in-the-loop, and data acquisition, among others.

In another embodiment, the carrier 110 may comprise an M-Series platform(e.g., from National Instruments), which may also support a variety ofmulti-slot chassis, e.g., a 16-slot chassis, an 8-slot chassis, a 4-slotchassis, among others. This and similar embodiments may facilitateeconomical portable measurements, such as, for example, by usinglow-cost communications modules (e.g., USB, 1394), and/or a low-cost1-slot USB bus adapter. This embodiment may not, for example, use a realtime program such as LabVIEW/RT. The carrier 110 may be configured witha RIO STC-like personality, such as, for example, a personality forgenerating synchronized, triggered waveforms. Cartridges suitable foruse with the carrier may have BNC, mass termination connectors. Thecarrier 110 may be implemented as a benchtop, desktop, in-vehicle,and/or rack-mounted system, as desired, and may be suitable for suchapplications as external/portable DAQ, in-vehicle testing, andrack-mount I/O for testing, among others.

Thus, in various embodiments, the RIO functionality of the measurementsystem may be comprised in or on various different components of themeasurement system.

FIGS. 8A and 8B—Block Diagrams of a Cartridge Carrier in a RIO System

FIGS. 8A and 8B are block diagrams of two embodiments of a cartridgecarrier 110 in a RIO system, i.e., a RIO carrier 110D. As both FIG. 8Aand FIG. 8B show, the RIO cartridge carrier 110, also referred to as a“RIO” 110D, may couple to computer system 102, as described above, andmay be operable to receive multiple cartridges 108, e.g., in respectiveslots in the RIO 110D. As FIGS. 8A and 8B also show, the RIO 110D mayinclude a programmable hardware element, e.g., an FPGA 308 which isoperable to be configured with a variety of measurement module interfaceprotocols (MMIPs), also referred to as “personalities”, in that theimplemented personality corresponds to a particular measurement module,module type, or module configuration/functionality. In one embodiment,each MMIP may be configured in a respective portion of the programmablehardware element 308. For example, the MMIP for cartridge 108A may beconfigured in portion 308A of the FPGA, the MMIP for cartridge 108B maybe configured in portion 308B of the FPGA, and so on.

FIG. 8A is a block diagram of an embodiment of the cartridge carrier orRIO 110D with separate cartridge controllers for each cartridge slot. Inother words, in this embodiment, the cartridge carrier includes separatechannels or buses 508A, 508B, 508C, etc. for each respective cartridgeslot, such that each cartridge inserted into the RIO carrier 110D maycommunicate with the FPGA 308 through a respective interface, channel,or bus.

FIG. 8B is a block diagram of an embodiment of the cartridge carrier orRIO 110D with a shared cartridge controller 508. Said another way, inthe embodiment of FIG. 8B, a single shared bus may provide forcommunication between cartridges 108 inserted into slots of the RIO 110Dand the programmable hardware element 308, e.g., FPGA, in the RIO 110D.In one embodiment, communication with the inserted cartridges 108 may beperformed by allocating respective time-slots for communication witheach cartridge 108, i.e., through time domain multiplexing (TDM), as iswell known in the art, although other techniques for communicating overa shared bus or interface are also contemplated. It is noted that inother embodiments, the RIO system may use other module forms besidescartridges. In other words, the concepts presented herein with respectto cartridge carriers 110 and cartridges 108 may be applied toembodiments where the modules are not specifically in the form ofcartridges. Further details of the RIO cartridge carrier 110D andcartridge controllers 508 are presented below with reference to FIGS. 9and 10, respectively.

FIG. 9—Block Diagram of a Cartridge Carrier

FIG. 9 is a block diagram of a RIO FPGA 308 comprised in a cartridgecarrier 110, according to one embodiment. In this embodiment, the RIOFPGA 308 may provide a hardware interface between controlling software,such as an application program executing on computer system 102 or onthe carrier 110D, for example, and the individual cartridge 108.

As FIG. 9 shows, the RIO FPGA 308 may be configured to include a varietyof interface components, including, for example, a bus interface 514 forcommunicating with a real time controller 550; a CPU interface 510 forcommunications between a processor (e.g., on computer system 102 or onthe carrier 110D) and portions of the FPGA configured with respectiveMMIPs, e.g., 308A-308F, as shown; and I/O interfaces 512 forcommunications between the FPGA MMIP portions and external signalconverters, such as ADCs 507 and DACs 509. As FIG. 9 further shows, theRIO FPGA 308 may also include one or more cartridge controllers 508,e.g., 508A-508C as shown, which facilitate communication between theFPGA MMIP portions and respective inserted cartridges 108A-108C. Asmentioned above with reference to FIGS. 4A-6, communications with thecartridges 108 may performed over a plurality of SPI lines 316, as wellas auxiliary lines, such as timing and trigger lines 314, collectivelyreferred to as SPI+ (SPI-Plus). One embodiment of a cartridge controller508 is provided below with reference to FIG. 10A.

FIG. 10A—Block Diagram of a Cartridge Controller

As mentioned above, the RIO FPGA 308 may include one or more cartridgecontrollers 508 which may provide the basic functionality necessary tointerface to a cartridge 108. FIG. 10A is a block diagram of oneembodiment of a cartridge controller 508, where the cartridge controlleris a component of a RIO system 110D, and where the cartridge controller508 provides for communication between the RIO FPGA 308 (describedabove) and an inserted measurement module/cartridge, e.g., cartridge108A. The cartridge controller 508 may behave much like other standardinterfaces to fixed resources on the RIO board, such as ADCs, DACs, andDIO. Additionally, the cartridge controller 508 may be configurable bythe MMIP portion of the FPGA 308, e.g., to mediate communications withthe cartridge in accordance with the configured MMIP. In variousembodiments, the cartridge controller 508 may be used as a fullyfunctional block or as part of an FPGA diagram, such as a LabVIEW FPGAdiagram.

Important aspects of the basic functionalities provided by the cartridgecontroller 508 include the facilities to detect cartridge insertion andto communicate with the EPROM 307 of a cartridge to identify thecartridge. The SPI interface, i.e., the plurality of wires coupling thecartridge controller 508 to the cartridge, is also used to communicatewith the cartridges functionally (as opposed to simple identification)and is designed to provide high performance communication between thecartridges 108 and the cartridge controller 508. Beyond the basicfunctionality, the cartridge controller 508 may include a set of modularblocks that may be included based on the needs of the implementation,including, for example, queues, timer, triggers, and digital I/O (DIO)support, described below. The cartridge controller block may alsoprovide hooks so that when instantiated as a component in a graphicaldiagram, such as a LabVIEW FPGA diagram, the diagram may be able toprovide user defined capabilities to the cartridge while maintainingbasic functionality necessary for identification, such as, for example,through a DIO line 522.

As FIG. 10A shows, the cartridge controller 508 may include pinmultiplexing 525 for coupling to the cartridge 108A. In a preferredembodiment, the measurement cartridges 108 are hot-swappable andinterchangeable, and may necessitate a notification mechanism whichoperates when a cartridge is removed or inserted. Thus, a moduledetection component 524 may also be included which may be operable todetect the cartridge 108A, e.g., via an ID select line 523, as shown. Inone embodiment, the cartridge controller 508 may monitor the ID selectline 513 for any transition when the controller 508 is not driving theline. The transition may be captured and a bit set to notify thecontrolling software by polled IO or interrupt. The software may thenread a status register to determine if a cartridge has been inserted orremoved from the slot so that it may take appropriate action, e.g.,reading the EPROM 307 on the cartridge 108 and configuring for aninsertion or clean up for removal. Identification of the cartridge maybe facilitated by the module detection component 524 in conjunction withan SPI rate and serializer component 527, also referred to as the SPIport 527, and an optional CPU interface 510A, which may provideinformation regarding configuration, status, interrupts, and DMA to aprocessor, e.g., on the carrier 110D or on the computer system 102. Inone embodiment, the CPU interface 510A may enable the cartridgecontroller 508 to be configured by the CPU, e.g., by the computer system102 or a processor on the carrier 110D.

In one embodiment, the ID select line 523 may be used to toggle betweencommunicating with the EPROM 307 for ID purposes, and communicating withthe cartridge for functional purposes, such as DAQ, control, etc. Inother words, the cartridge may support the ID Select cartridgedetection, and may also support SPI for reading the identificationEPROM. When not in identification mode, the cartridge pins may bedefined and used for any purpose, thus allowing for future flexibility.In one embodiment, two primary modes may be defined for the cartridgecontroller 508. In a basic SPI mode, the cartridge controller 508 maycommunicate over the SPI port 527 and use pins for converting data,indicating busy, and exchanging triggers and clocks. In another mode,the cartridge controller 508 may use eight pins for digital input andoutput. Upon power up or upon a cartridge change, the controller 508 mayenter a tristate (high-Z) mode in which all the pins are tristate forprotection. After reading the EPROM 307, the software may set theappropriate mode as needed.

In one embodiment, the cartridge controller may support a DIO mode whichprovides basic digital input and output reads allowing communicationwith static DIO pins. For example, the DIO mode may include timed DIOand may support buffered DIO, e.g., for control applications.

As mentioned above, primary timing signals may be sent to the cartridgethrough one or more timing signal lines, included in the SPI+ interface.The cartridge controller 508 may provide a multiplexer for selecting aconversion signal from the local timer or system triggers. The systemtriggers may include a local “RTSI” bus and signal from user definedhardware. In one embodiment, the cartridge may provide a trigger signalthat may be routed to the system triggers.

As FIG. 10A also shows, the cartridge controller 508 may also include aninput data queue 534, as well as an output command queue 531 and anoutput data queue 532, for communicating with the MMIP portions of theFPGA, as well as the CPU interface 510A. As also shown, a DIO component522 may also be included to facilitate digital communications betweenthe cartridge 108A (via the pin multiplexing 525) and the MMIP portionsof the FPGA 308. Similarly, a timer/trigger component 528 may beincluded for communicating timing and triggering signals to and from thecartridge 108A, as shown.

A flow control component 526 may operate to regulate or direct data flowbetween the output command queue 531, the SPI rate and serializercomponent 527, and the cartridge 108A. In one embodiment, the SPI rateand serializer component 527 may also be coupled to the cartridge (viapin multiplexing 525) through a plurality of SPI lines 529, e.g., CLK(clock), MISO (master in, slave out), and MOSI (master out, slave in)lines, as shown, which may provide for communication of clockingsignals, as is well known in the art.

Thus, an efficient SPI port 527 may be desirable for communication notonly with the ID EPROM 307 of the cartridge 108A, but also forfunctional communication with inserted cartridges 108. Many of thecartridges may be based on a variety of available SPI compatible oreasily adaptable ADCs or DACs. SPI hardware/software interfaceperformance may be a primary determining factor in the overallmeasurement system performance. In addition to the basicparallel-to-serial and serial-to-parallel conversion necessary tocommunicate efficiently, the SPI port 527 may provide a number offeatures to reduce software burden, including, for example, data queuesto buffer data in each direction and hardware flow control. The dataqueue may allow blocks of data to be transferred from the software andto take up latency when the software is busy.

The SPI port 527 may also take over part of the control role for thecartridge 108A since the cartridge is simple by design. As FIG. 10Ashows, the output queue may include “commands”, as indicated by theoutput command queue 531, as well as data, as indicated by the outputdata queue 532, that indicate the addressing modes, whether to capturedata, and flow control, among others. In addition a reload mode may beprovided which allows a sequence of data/command to be repeated withoutsoftware intervention. A common use case would be to load data necessaryto configure a set of ADC reads, including waiting for conversionresponses. With the output queue repeating, the software need onlymanage capturing the input data.

In one embodiment, the SPI rate, i.e., the rate of data flow, may beconfigurable for each controller and may be changed on the fly to allowthe maximum performance for a particular IC and topology. For example,the cartridge's EPROM 307 and ADC 507 may support different transferrates via SPI. FIG. 10B illustrates a typical SPI cycle, according toone embodiment. As FIG. 10B shows, chip select signals 1002 may beasserted one half SPI period before the falling edge of an SPI clocksignal 1004 and held a half period at the end of the cycle. Thecontroller may drive data on the falling edge and sample the data on therising edge of the SPI clock signal 1004.

As is common in high performance serial controllers, the input queue 534and output queues 531 and 532 may provide a level of decoupling betweenthe software and the hardware, i.e., the FPGA. The buffers may allowsystem latencies to be absorbed and lessen the processor load. The queuesize may be adjusted for an implementation target, for example, a goodminimum target may be one scan of data for a typical cartridge (fourchannels 32 bits). As mentioned above with respect to SPI, the outputqueues 531 and 532 may contain data and control information and may beset to automatically reload. The input queue 534 may capture data fromthe SPI input stream when indicated by the output command. Each of thequeues may have optimized software interfaces for efficiently managingsingle point and buffer operations. Additionally, DMA capability mayalso be included for maximum performance where possible.

Because of the simplicity of the cartridge 108, the responsibility forproviding compatible timing signals may fall on the controller 508. Thetimer 528 may provide for polarity and pulse width control of a signalthat may be routed to the cartridge through a timing line. The timer maybe used independently or as part of coordinated system timing withrouting and hardware enables. An additional benefit is that the localtimer may allow the cartridge to be completely functional withoutrelying on system resources. FIG. 10C illustrates one embodiment of acommon timer waveform 1010 where the initial polarity is high, and thewaveform generates two periods low followed by three periods high.

An important feature in communicating with an ADC or DAC is the abilityto determine or direct flow control, for example, waiting for a BUSYsignal from the cartridge indicating the conversion is done, or a timerindicating when to write updates to a DAC. Wait blocks in conjunctionwith the output command queue 531 may allow the condition to bespecified. In one embodiment, at any time, two conditions may bemonitored. The source of the event and the desired edge may beprogrammed. When the wait command is at the head of the queue, the linemay be monitored and the SPI data may not be transferred until thecondition has occurred.

While the cartridge controller 508 may provide the necessary facilitiesto communicate and control most cartridges, more complex andsophisticated system functions may be realized by connecting to externalresources, such as those available through LabVIEW FPGA, via externalhooks. These hooks may provide for custom timing or triggering bycoupling a diagram to timing and triggering signals. For improvedflexibility, all the available pins may be made available to the user'sdiagram to provide complete control of the cartridge 108 while stillallowing the controlling software to detect and identify cartridges viaa standard mechanism. An example is coupling custom counter timers totransform a digital module. The external hooks may also be used to builda standard configuration of timing and triggering resources.

Registers

The following is an exemplary register set for the cartridge controller,representing one embodiment of a set of controls used for communicatingwith and controlling components of the cartridge controller 508. It isnoted that these registers are exemplary only, and are not intended tolimit the register set used by the invention to any particular set orinterpretation.

uD Status Register Read 16 bit Offset 0x00 uD Dout FIFO Status Read 16bit Offset 0x02 uD Din FIFO Status Read 16 bit Offset 0x04 uD Din FIFORead 16 bit Offset 0x08 uD DIO In Register Read 16 bit Offset 0x0C uDSignature Read 16 bit Offset 0x0E uD Control Register Write 16 bitOffset 0x00 uD SPI Rate Register Write 16 bit Offset 0x02 uD Timer ARegister Write 16 bit Offset 0x04 uD Action Register Write 16 bit Offset0x06 uD Dout FIFO Register Write 16 bit Offset 0x08 uD Control 2Register Write 16 bit Offset 0x0A uD Timer B Register Write 16 bitOffset 0x0C uD DIO Out Register Write 16 bit Offset 0x0EFIG. 11A—Measurement Module and Generalized Re-Configurable CarrierArchitecture

FIG. 11A is a block diagram of an architecture for a measurement systemwhich includes a measurement module 108 and a RIO carrier 110D, alsoreferred to as a generalized carrier 110D. As mentioned above, ageneralized carrier with multiple cartridge slots may be configured withmultiple interfaces for inserted cartridges, such that each cartridge'sinterface is implemented by the carrier. For example, if threecartridges with three different respective interfaces are inserted inthree slots of the RIO carrier 110D, then the RIO carrier 110D may beconfigured to implement the three interfaces. Similarly, if multiplecartridges are sequentially inserted into and removed from a particularslot, the RIO carrier 110D may be configured respectively for eachcartridge, i.e., sequentially. The RIO carrier 110D may further beoperable to couple to any of various products or platforms.

In one embodiment, a channel or bus may be provided by the generalizedcarrier 110D for each cartridge/interface protocol. In other words, eachslot may have an associated dedicated bus for that slot, with acorresponding portion of the generalized carrier's reconfigurablehardware configurable to implement the interface for a cartridgeinserted into the slot. In another embodiment, the generalized carrier110D may include a shared bus or backplane common to a plurality of theslots, where inserted cartridges may communicate through the common busor backplane with the reconfigurable hardware of the generalized carrierin accordance with the respective interface protocols implemented on thereconfigurable hardware.

As mentioned above, in another embodiment, the generalized carrier maybe configurable to include not only the adaptive interface functionalitydescribed above, but may also include or may be configured to include,one or more measurement and/or control functions.

As FIG. 11A shows, the measurement system may include measurement module108, similar to that described above with reference to FIGS. 5A-5C. Themeasurement module 108 may couple to the generalized carrier 710 throughone or more communication lines or terminals, as shown. The generalizedcarrier 110D may in turn be operable to couple to any of variousproducts or platforms 720, as indicated.

In one embodiment, the measurement module 108 may include connectors 301for (analog) signal I/O, i.e., for communicating with a sensor oractuator 112. As shown, the connectors 301 may couple to signalconditioning circuitry 302, which in this embodiment includes a signalconditioner and a MUX. The signal conditioning circuitry 302 may coupleto signal conversion circuitry, such as the ADC 304 shown, which may inturn couple to isolation circuitry 305, described above with referenceto FIG. 5C. In this embodiment, the measurement module 108 also includesan EEPROM 106A containing the EDS which may be operable to communicatethe interface protocol information to the carrier 110D, as alsodescribed above. Thus, the measurement module 108 may provide a physicalconnection between the sensor or actuator 112 and the carrier 110D, aswell as signal conditioning, digitization, and isolation functions forthe measurement system. In addition, in one embodiment, the measurementmodule 108 may provide identification (for Plug-and-Play (PnP)) and/ordigital I/O (parallel and/or serialized) functionality. For example, themeasurement module or cartridge may be, or function as, a communicationcartridge, e.g., an RS232 or RS485 cartridge.

As indicated in FIG. 11A, the generalized carrier 110D may includefunctional unit 106, here shown as FPGA 308, which may be programmableto implement the interface specified by the measurement module 108, asdescribed in detail above. In this embodiment, the generalized carrier110D may also include a register set 712, through which communicationwith the products/platforms may be effected. In various embodiments, thegeneralized carrier 110D may provide additional functions which mayinclude I/O scanning, timing and triggering, power-on states, logic,digital I/O timing/counting, data transfer and support for parallel andscanned backplanes, among others.

In the RIO system, the FPGA 308 may be configurable with a measurementor control function, including, but not limited to, timing, triggering,synchronization, signal processing, and analysis. Thus the FPGA 308 mayperform a measurement/control function instead of, or in addition to,the computer system 102.

The products and platforms 720 indicated in FIG. 11A may provide meansfor the carrier 110D to communicate with external systems. For example,an Application Programming Interface (API) 722 may allow externalsystems to read and/or write to the registers in the register set 712 tocommunicate and/or control the measurement system. For another example,a processor, e.g., a micro-controller 724, and a network interface card726 may couple the registers to a network 104, through whichcommunications with external systems may be facilitated. In oneembodiment, the products and platforms 720 may be comprised in thecarrier 110D, while in other embodiments the products and platforms 720may be external to the carrier 110D, e.g., may be comprised in computersystem 102.

FIG. 11B—Measurement System Partitioning

FIG. 11B is a block diagram illustrating functional partitioning amongcomponents of a RIO-based measurement system with a plurality ofmeasurement modules. More specifically, FIG. 11B shows the partitioningof functionality between domains of the application (e.g., LabVIEW)1180, RIO 1170, and the measurement modules 1160.

As FIG. 11B shows, the measurement module domain 1160 may be responsiblefor signal input via module connectivity 301, as well as signalconditioning 302, and data conversion, via converters such as ADCs 304Aand 304B comprised in the measurement modules 108. As FIG. 11B alsoshows, timing and triggering 1130 may be handled in the RIO domain 1170,for example, by a digital data back-end 1102, timing engine 1104, andone or more counter/timers 1106, all comprised in the RIO carrier 110.Processing/Logic operations 1140 of the measurement system may beprovided by driver 1108 and control logic, EU scaling, and alarms 1110,and may also utilize the digital data back-end 1102, timing engine 1104,and one or more counter/timers 1106 to some extent, as shown. Is shouldbe noted that the processing/logic capabilities 1140 of the system maybe shared by the RIO 1170 and the application, i.e., LabVIEW 1180, asindicated by the overlap between the RIO domain 1170 and the LabVIEWdomain 1180. Finally, analysis, DSP, display, reporting, and monitoringcapabilities 1120 may be provided by the application 1150 (functioningin a supervisory capacity), i.e., in the LabVIEW domain 1180. It isfurther noted that this supervisory capacity may in part involve use ofthe control logic, EU scaling, and alarms 1110, as shown.

Thus, in one embodiment, the various functionalities of the measurementsystem may be partitioned among the measurement module domain 1160, theRIO domain 1170, and the application (LabVIEW) domain 1180.

FIG. 12A—PXI Card Based Carrier

FIG. 12A illustrates a carrier 110B comprising a PXI card, i.e.,implemented on a PXI card, according to one embodiment of the invention.The PXI card 110B may be operable to plug into a PXI chassis or asuitably equipped computer system 102, and may implement the carrierfunctionality described above, i.e., the PXI card 110B may include (inaddition to PXI interface circuitry 610) a functional unit 106 which isprogrammable or configurable to implement an interface based oninterface protocol information transmitted from a coupled measurementmodule 108, as described above. As also described above, the carrier110B (PXI card) may be operable to couple to (or be comprised in)computer system 102 to facilitate the described programming by thecomputer system 102. Alternatively, the PXI card may include computersystem 102, e.g., may include a processor and memory in the form of a“PC on a card”. It should be noted that other card based implementationsbesides the PXI card implementation are also contemplated, for example,PCI, Infiniband, or other protocols or platforms may be used toimplement a carrier, the PXI card embodiment being but one example.

As FIG. 12A shows, in one embodiment, the PXI card 110B may include amemory 604 coupled to the functional unit where configurationinformation or program instructions may be stored for deployment orexecution on or by the functional unit 106. The PXI card may alsoinclude at least one measurement module connector 606 whereby ameasurement module 108 may be attached or coupled to the PXI card, andwhich facilitates communication between the PXI card 110B and themeasurement module 108.

In one embodiment, implementing the carrier in a PXI board 110B (orother card implementation) may provide integrated signal conditioning,modularity, and an interface to plug and play sensors. Additionally, insome embodiments, these features may be provided at a lower cost thanprior art systems.

FIG. 12B—PDA with Carrier and Measurement Module

FIG. 12B illustrates another embodiment of a carrier unit 110 andmeasurement module 108. As FIG. 12B shows, in one embodiment, thecarrier unit 110 may comprise or be coupled to a Personal DigitalAssistant (PDA). In the embodiment shown, PDA 102B is operable to coupleto carrier 110C, which may be implemented as an adaptor which isoperable to couple to the PDA 102B through a standard communication orexpansion port on the PDA 102B. In another embodiment, the carrier 110C.may be comprised in the PDA 102B, i.e., may not be a detachable module.For example, the PDA 102B may itself be the carrier.

The carrier 110C may be operable to couple to a measurement module 108G,as shown. The measurement module 108G may in turn be operable to coupleto a sensor or actuator 112, as described above. In one embodiment, PDA102B may be operable to program the carrier 110C. (i.e., the carrierunit's functional unit) with the interface protocol information providedby the measurement module 108G, as described in detail above.Alternatively, the PDA 102B may be programmed as the carrier unit. Inone embodiment, the PDA 102B may be further operable to providefunctionality related to a measurement, DAQ, and/or control task oroperation. In other words, in addition to acting as a developmentplatform for the carrier 110C/measurement module 108G, the PDA 102B mayalso operate in a measurement and/or control capacity in conjunctionwith the carrier 110C. and measurement module 108G. In anotherembodiment, the PDA 102B may be used as an interface to another computersystem, e.g., computer system 102. For example, a suitably equipped PDA102B may provide wireless communication for the carrier 110C/measurementmodule 108G.

FIG. 12C—RIO System with External I/O Expansion

FIG. 12C illustrates several embodiments of the invention using RIO 110D(generalized carrier 110D, described above with reference to FIG. 7)with external I/O expansion, i.e., with additional I/O connections forcoupling to a plurality of measurement modules 108. As FIG. 12C shows, aRIO cartridge or card 110D may provide connectors for analog I/O 810and/or digital I/O 820. As may be seen, without the use of expansion I/Odevices, the number of measurement modules 108 which may be coupled tothe RIO card 110D may be limited, e.g., to one.

In one embodiment, the digital I/O 820 may couple to a breakoutbackplane 804, for example, via parallel SPI buses 830, as shown,although other buses for coupling the I/O expansion devices to thecarrier 110D are also contemplated. The breakout blackplane 804 mayprovide connectivity for a plurality of measurement module cards orcartridges 108, and may thereby be operable to facilitate external,synchronized, and conditioned I/O 850 for the measurement system. Forexample, each measurement module or cartridge 108 comprised in or on thebreakout backplane 804 may be operable to couple to a sensor or actuator112. Each measurement module 108 may also couple to the backplane 804.The breakout backplane 804 may then facilitate synchronization betweenthe various measurement modules 108. Additionally, as described above,the measurement modules 108 may provide any of a variety of DAQ,measurement, and control functions, including signal conditioning andconversion, and thus external, synchronized, and conditioned I/O 850capabilities may be included in this embodiment of the invention.

In another embodiment, the RIO card or device 110D may couple to anaddressable backplane 806, for example, through an SPI with slot selectcapabilities 840. In other words, the addressable backplane 806 mayprovide a plurality of individually addressable slots for a plurality ofmeasurement modules or cartridges 108, described above, which may eachbe individually targeted for communication by the carrier 110D.Additionally, the addressable backplane 806 may be expandable, i.e.,additional addressable backplanes 806A may be coupled to the addressablebackplane 806 to provide additional slots for additional measurementmodules 108. Thus, in this embodiment, expandable, conditioned I/Ocapabilities 860 may be provided by the system.

In yet another embodiment, the RIO card or device 110D may couple to a“DAQ in the cable” 808, where a measurement module 108H may be comprisedin a cable connector. In other words, the features of a measurementmodule 108, as described above, may be included in one or bothconnectors of a cable, as shown. For example, in the example of DAQ incable 808A, one end of the cable may be coupled to the RIO device 110D,and the measurement module/connector 108H may be operable to couple to asensor or actuator 112. In another example, the DAQ in cable 808B maycomprise measurement module 108H which may be operable to couple to theRIO card 110D, and another cable connector (without a measurement module108H) for coupling to a sensor/actuator 112.

Thus, in various embodiments, the functionality of one or moremeasurement modules 108 may be provided through the use of I/O expansiondevices (e.g., devices 804, 806, and 808) which may extend the I/Ocapabilities of the carrier 110, or RIO device 110D. Furthermore, insome embodiments, additional functionality may be provided by theexpansion device, such as the ability to synchronize the I/O.

FIG. 12D—Measurement System Platform Extensions

FIG. 12D illustrates various embodiments of the measurement system usinga variety of the platform extension technologies described above. Itshould be noted that the system extensions shown are meant to beexemplary, and are not intended to limit the type of extensions/devicesused in the measurement system.

As FIG. 12D shows, in one embodiment, the system may include a PCI orPXI chassis 902 (cartridge carrier 110A) with measurement cartridges108D, as described above with reference to FIGS. 5-12A. Note that otherbuses/chassis besides PCI and PXI may also be used. For example, aFieldPoint system 904 (from National Instruments) may provide thechassis, slots, and backplane to accommodate the plurality ofmeasurement cartridges 108D. As shown, one or more of the measurementcards or cartridges 108 may couple to one or more sensors or actuators112, which may include one or more Plug and Play (PnP) sensors. Thusthese embodiments may provide local I/O using established platforms(PCI, PXI, FieldPoint, etc.) and integrated signal conditioning, as wellas interfaces to PnP sensors, as shown.

In another embodiment, a generalized carrier, i.e., a RIO device 110D asdescribed above with reference to FIGS. 11 and 12C, may provide modularI/O and signal conditioning, and may also provide an interface to PnPsensors, as well as regular sensors and actuators 112. It is noted thata RIO system may be implemented in any of the systems shown in FIG. 12D.

In another embodiment, USB/Ethernet devices 908 may be used to providelow-power, low-cost measurement systems, where USB/Ethernetcommunication functions may be provided by an expansion card on apersonal computer (e.g., a laptop, or PDA), or by an inexpensivecontroller which may be comprised in another device. For example, suchsystems may include “good” class waveform data acquisition capabilities,have a small form factor, i.e., a small size, and may also provide formodular measurements through the use of small detachable measurementmodules 108, as described above. Thus, a plurality of sensors 112,possibly including PnP sensors, may be fielded using USB/Ethernet (orother buses/transmission media) in an affordable manner.

In yet another embodiment, highly distributed measurement systems basedon networked measurement nodes 910 may be developed using PXI orFieldPoint (or any other suitable platform) and a plurality ofdistributed carriers 110 and/or measurement modules 108. In oneembodiment, measurement systems may be distributed over a wide areanetwork, such as the Internet. Such systems may provide integratedsignal conditioning using small inexpensive components (carriers 110,measurement modules 108, and/or sensors 112), such as PDAs, wirelesssmart sensors, linked modular measurement devices, etc., therebyproviding a low-risk, low-cost measurement solution. For example, thesystem may be suitable for low-risk deployment on emerging networks.

Thus, the use of measurement modules 108 in combination with a varietyof carrier units 110 and computer systems 102 provides a broad range ofapproaches for efficient and affordable measurement systems, includingestablished platforms such as PCI/PXI 902 and FieldPoint 904,generalized carriers 110D such as RIO, new USB/Ethemet devices 908, andsmall networked measurement nodes 910.

FIG. 13—Platforms and Technology

FIG. 13 illustrates embodiments of the present invention in the contextof current art with respect to platforms, DAQ architectures/engines, andsignal conditioning. As FIG. 13 shows, a plethora of differentmeasurement, DAQ, and/or control systems may be developed using variouscombinations of base platforms 1002, DAQ architectures/engines 1004, andsignal conditioning devices or systems 1006.

For example, any of a number of base platforms 1002 may be used toprovide a connectivity infrastructure for the system, including, but notlimited to, PXI 902A, PCI 902B, DAQPads 1008 (from National Instruments)which may utilize USB, 1394, etc., FieldPoint 904, small networkedmeasurement nodes 910, and PDAs/handheld computers 102B.

DAQ architectures/engines 1004 which may be selected include, but arenot limited to, the National Instruments E Series of DAQ devices 1010,FieldPoint/BlueBus 1012, RIO 110D, and small form-factor measurementmodules 108.

Signal conditioning technologies 1006 which may be used in such systemsinclude (but are not limited to) SCXI 1020, SCC 1022, and 5B 1024 signalconditioners, as well as FieldPoint/BlueBus compliant signalconditioners, and measurement modules 108, such as National Instrumentssmall form-factor measurement modules.

As FIG. 13 indicates, components or standards may be selected from eachclass of component (platforms 1002, engines 1004, signal conditioners1006), and, depending on compatibility, combined to develop a widevariety of measurement systems. For example, a PXI platform 902A may becombined with E Series devices 1010, RIO 110D, and measurement modules108, while a PCI platform 902B may be combined with E Series devices1010 and measurement modules 108, but not RIO 110D.

More generally, PXI 902A, PCI 902B, and DAQPads 1008 platforms may becombined with E Series instruments 1010, and, along with FieldPoint 904platforms, may also be combined with measurement modules 108. TheFieldPoint platforms 904 may also be combined with theFieldPoint/BlueBus architecture/engine and signal conditioning devices1012. Small networked measurement nodes platforms 910 (including CAN,Ethernet, wireless media, etc.) and PDA/handheld computers 102B may becombinable with the measurement modules 108, as described above, for DAQengine functionality 1004 and signal conditioning 1006.

As FIG. 13 also shows, the E Series devices/engines 1010 may becombinable to with SCXI 1020, SCC 1022, and 5B 1024 signal conditioners,while the RIO engine 110D may be combinable with the measurement modules108.

Thus, the use of measurement modules 108 and various carrier units 110may provide complementary and overlapping functionality as compared tocurrent approaches to development of measurement systems, and may alsoprovide substantial cost, efficiency, and flexibility benefits, asdescribed in detail above. In particular, the use of the measurementmodules 108 with carriers 110 leverages disruptive semiconductortechnology to deliver highly modular DAQ/Signal Conditioning/Conversionfunctionality which is reusable in many platforms, e.g., USB, Ethernet,FieldPoint, RIO, PDAs, etc., and which lowers risk and effort insupporting new platforms, such as wireless, CAN, etc. In one embodiment,this technology is generally capable of providing “good” class DAQ,e.g., up to ˜50 kSamples/s, although it is also contemplated that as theperformance of hardware improves, higher performance DAQ may also bepossible using the present invention.

FIG. 14—Method for Configuring a Measurement System

FIG. 14 is a flowchart of a method for configuring a measurement system,according to one embodiment of the invention. It should be noted that insome embodiments, various of the steps may occur concurrently, in adifferent order than shown, or may be omitted. Furthermore, one or moreadditional steps may be performed as desired.

As FIG. 14 shows, in 1402 a measurement module 108 may be coupled to acarrier unit 110. For example, the measurement module 108 may be coupledto the carrier unit 110 via a serial bus, a parallel bus, wirelesstransmission medium, a network, or edge connection or any othercommunication medium. In a typical embodiment, the measurement module108 is a card or cartridge that can be inserted into a slot of thecarrier unit 110. In this embodiment, the carrier unit 110 may comprisea plurality of slots adjusted to receive different measurement modules108.

In 1404, the carrier unit 110 may be coupled to a computer system 102.In one embodiment, the carrier unit 110 may be coupled to the computersystem 102 via a serial bus such as an SPI cable. In other embodiments,the carrier unit 110 may be coupled to the computer system 102 throughvarious communication media, including, but not limited to, a serialbus, a parallel bus, wireless transmission medium, a network, such asthe Internet, or any other communication medium. In another embodiment,the carrier unit 160 may include computer system functionality, e.g.,the carrier unit 110 may include a processor, micro-controller, or a“computer on a card” that performs a desired processing function. Inthis embodiment, step 1404 (and 1408 below) may be unnecessary.

In 1406 the measurement module 108 may communicate interface informationto the carrier unit 110, where the interface information specifies aninterface for operating with the measurement module 108. For example, asnoted above, in one embodiment, the interface information may be in theform of an EDS (Electronic Data Sheet) structure. In another embodiment,the interface information may simply be identification information,e.g., a module ID, which may then be used to retrieve the interfaceprotocol for the module.

In 1408, the carrier unit 110 may communicate the interface informationto the computer system 102. It is noted that steps 1406 and 1408 may beperformed as one step when measurement module communicates the interfaceinformation directly to the computer system 102.

Finally, in 1410, the computer system 102 may use the interfaceinformation to program a functional unit 106 on the carrier unit 110,thereby implementing the specified interface in the carrier unit 110.For example, in an embodiment where the interface information includesthe interface protocol for the module 108, the computer 102 may programthe carrier unit 110 with the interface information. Alternatively, inan embodiment where the interface information comprises a module ID, thecomputer 102 may use the module ID to retrieve or select an appropriateinterface protocol, such as from a memory medium of the computer system102 or from a server 102A coupled to the computer system 102, andprogram the carrier with the interface protocol, e.g., with a bitstreamimplementing the interface protocol. After the carrier unit 110 has beenprogrammed, the carrier unit 110 and the measurement module 108 may betogether operable to perform one or more of a data acquisition,measurement, and control task or function.

It is noted that in an embodiment in which the carrier 110 includes aprocessor and memory, i.e., includes the computer 102, steps 1404 and1408 may be omitted, and thus, in 1410, the processor and memory on thecarrier 110 may program the functional unit of the carrier 110 with thecommunicated interface protocol.

In one embodiment, the method may further include the carrier unit 110and the measurement module 108 together performing the task or function.

FIG. 15—Another Method for Configuring a Measurement System

FIG. 15 is a flowchart of another method for configuring a measurementsystem comprising a computer system 102 coupled to or comprising ameasurement device. The measurement device may comprise a carrier unit110 and one or more measurement modules 108. The carrier unit 110preferably includes a functional unit 106, as described above. Asmentioned previously, in some embodiments, various of the steps mayoccur concurrently, in a different order than shown, or may be omitted.Furthermore, one or more additional steps may be performed as desired.

As shown in FIG. 15, in 1502, a program may be created on the computersystem 102 which implements a measurement function. As mentioned above,a measurement function may include any of a measurement (including dataacquisition) or control task or function. It should be noted that in apreferred embodiment, the program may comprise a graphical program,i.e., the program may comprise a plurality of interconnected nodes whichvisually indicate functionality of the graphical program, such as aLabVIEW VI. However, in other embodiments, the program may beimplemented in any other programming language or system, including C,C++, Java, and Visual Basic, among others. In one embodiment, theprogram may be programmatically created in response to user inputreceived to a wizard-like interface, as described in U.S. patentapplication Ser. No. 09/745,023 titled “System and Method forProgrammatically Generating a Graphical Program in Response to ProgramInformation,” filed Dec. 20, 2000, which was incorporated by referenceabove.

In 1504, the (graphical) program may be deployed on the functional unitof the device, i.e., of the carrier, where after the deployment of theprogram the functional unit implements the measurement function of theprogram. In other words, the functional unit is operable to perform themeasurement function encoded in the program. As mentioned above, themeasurement function may include one or more of data acquisition,measurement, and control functions, as desired.

In an embodiment where the functional unit on the device is a processor,deploying the program on the functional unit of the device may includetransferring the program to a memory on the device (i.e., carrier 110)for execution by the processor. In one embodiment, this may includetransferring the program in its native format to the memory and theprocessor executing the program, e.g., using a graphical programexecution engine and possibly a RTOS (real time operating system).Alternatively, the program may be compiled into an executable program(e.g., machine language, a script, or an interpretable data structure)and transferred to the memory for execution by processor.

In an embodiment where the functional unit on the device is aprogrammable hardware element, e.g., an FPGA, deploying the program onthe functional unit of the device may include converting the programinto a hardware description, such as a VHDL file, which may be compiledand used to program the FPGA to perform the measurement function. Forexample, the hardware description may be converted into an FPGA-specificnetlist which describes the components required to be present in thehardware as well as their interconnections. Conversion of the hardwaredescription into the FPGA-specific netlist may be performed by any ofvarious types of commercially available synthesis tools, such as thoseavailable from Xilinx, Altera, etc. The netlist may be compiled into anFPGA program file, also referred to as a software bit stream or hardwareconfiguration program, which can be readily downloaded to program theFPGA. After the netlist has been compiled into an FPGA program file theFPGA program file may be transferred to the FPGA, thereby producing aprogrammed hardware equivalent to the program.

In 1506, the functional unit, i.e., the carrier 110, may optionallyexecute the deployed program to perform the measurement function. Saidanother way, the measurement system may perform the measurement functionvia execution of the program by the functional unit on the device, i.e.,the carrier 110.

FIG. 16—Method for Performing a Measurement Function

FIG. 16 is a flowchart of a method for performing a measurementfunction, according to one embodiment of the present invention. As notedabove, in some embodiments, various of the steps may occur concurrently,in a different order than shown, or may be omitted. Furthermore, one ormore additional steps may be performed as desired.

In 1602, a signal may be acquired. For example, a measurement modulecoupled to or comprised in a carrier unit may acquire the signal. Thesignal may originate from a sensor or actuator 112, or may betransmitted from an external system.

In 1604, the measurement module 108 may perform one or more of signalconditioning and signal conversion on the acquired signal, as describedin more detail above. For example, the measurement module may performfiltering, gain adjustments, ADC or DAC, etc. on the signal. Inperforming the signal conditioning and/or signal conversion on theacquired signal, the measurement module 108 may generate data, e.g.,results data, which may include one or more of the original signal, theconditioned and/or converted signal, or information derived from orgenerated in response to the signal.

In 1606, the measurement module 108 may provide the data to the carrierunit 110 according to an interface protocol, e.g., the interfaceprotocol described above.

Then, in an embodiment where a functional unit on the carrier 110 hasbeen programmed or configured appropriately, in 1608, the functionalunit on the carrier 110 may perform a measurement function, e.g., on thesignal or data. In other words, the carrier 110 may perform ameasurement function which was programmed into the functional unit. Forexample, the carrier 110 (i.e., the functional unit on the carrier 110)may perform any of various data processing operations on the data, suchas filtering, analysis, digital signal processing, pattern recognition,or other analysis. For another example, the carrier may generate controlsignals in response to an analysis of the data, such as to control oneor more plant or manufacturing operations.

In another embodiment in which the computer system 102 comprisesmeasurement software for performing a measurement function, in responseto 1606 above, the carrier unit 110 may provide the data to the computersystem 102, as indicated in 1610. Then, in 1612, the computer system 102may perform the measurement function, e.g., on the signal, where themeasurement function may include data acquisition, measurement, and/orcontrol functions, as described above. In another embodiment, thecarrier unit 110 may perform a portion of the measurement analysis orcontrol function and the computer system 102 may perform the remainingportion of the measurement analysis or control function.

FIG. 17—Method for Registering a Measurement Module Interface Protocolfor a Measurement Module

In one embodiment of the present invention, rather than the module orcartridge 108 providing the MMIP (measurement module interface protocol)to the carrier 110 (or computer 102), the MMIP for the cartridge may bestored on an MMIP server 102A, as described above with reference to FIG.1B.

FIG. 17 is a flowchart of a method for registering an MMIP program for ameasurement module with the MMTP server 102A, according to oneembodiment of the present invention. As noted above, in someembodiments, various of the steps may occur concurrently, in a differentorder than shown, or may be omitted. One or more additional steps mayalso be performed as desired.

As FIG. 17 shows, in 1702, a measurement module 108 according to thepresent invention may be created, e.g., by a manufacturer. As describedabove, the measurement module 108 may include any of a wide variety offunctions for use in a measurement system, including for example, signalconversion and signal conditioning, among others. The measurement module108 may have associated with it an MMIP which codifies the communicationinterface for the module 108, as also described above.

Then, in 1704, a program may be created which implements the measurementmodule's MMIP. In one embodiment, a plurality of programs may be createdfor the module 108, where each program implements a different interfacefor the measurement module. In other words, each program may facilitatea different function set or communication interface for the module 108.As also described above, each program may be deployable on the carrierto configure the carrier to support or implement the corresponding MMIP.In an embodiment where the carrier's functional unit is a processor andmemory, the program may be executable by the processor, therebyimplementing the module's MMIP. In one embodiment, the program maycomprise a graphical program, e.g., a LabVIEW graphical program. Inanother embodiment, the carrier's functional unit may comprise aprogrammable hardware element 106, such as an FPGA, in which case, theprogram may comprise a bitstream which is deployable on the FPGA toimplement the MMIP. Thus, one or more programs may be created for themeasurement module codifying a corresponding one or more measurementmodule interface protocols for respective functional configurations orversions of the measurement module.

In 1706, the MMIP server 102A may be accessed, for example, via acomputer system operated by, or on behalf of, the manufacturer or arelated entity, such as a wholesaler or retailer. In one embodiment, theMMIP server 102A may be accessed over a network, such as the Internet,although other methods of access may be used as well.

In 1710, the measurement module 108 may be registered with the MMIPserver 102A. For example, identification information for the module 108,such as an ID or functional description, may be provided to the server102A. As other examples, information identifying the manufacturer, ahelp file describing the use and operation of the module, platforminformation, time and date information, and/or any other usefulinformation for registration of the measurement module 108 may beprovided to the MMIP server 102A. In one embodiment, an icon mayoptionally be provided for representing the module 108 in a graphicalenvironment, such as in a palette or configuration diagram.

Finally, in 1712, the program(s) may be provided to the MMIP server 102Afor storage on the server 102A, or on a memory medium coupled to andaccessible by the server 102A. The MMIP server 102A may subsequently beaccessible by clients for retrieval of the stored program(s), asdescribed below with reference to FIG. 18.

In one embodiment, the MMIP program(s) may be created initially as agraphical program, such as a LabVIEW graphical program (oralternatively, as a text-based program). As is well-known in the art, ingeneral, compilation of a program to an FPGA bitstream often requires asubstantial amount of time, e.g., hours. Thus, the registering entity,e.g., the manufacturer, may create the graphical program(s) (ortext-based program(s)), and compile the program(s) to a bitstream (ormultiple bitstreams) suitable for deployment on an FPGA. Thebitstream(s) may then be stored on the server 102A, as described above.

In another embodiment, the manufacturer (or other entity), may createthe graphical (or text-based) program(s), and register the module andprogram(s), as described above. The MMIP server 102A, or anothercomputer system, may then compile the program(s) into correspondingbitstreams for deployment on an FPGA. The resulting bitstream(s) maythen be stored for access by clients, as described below. In yet anotherembodiment, the graphical program(s) (and/or text-based program(s)) andthe bitstream(s) may be registered with the MMIP server 102A, such thatthe MMIP may be provided to clients with different carrier platforms,e.g., processor/memory based carriers and FPGA based carriers.

In the case where a module is configurable to perform a variety ofdifferent functions, the module may have a corresponding variety ofinterface protocols which may be provided or specified to the server aspart of the measurement module registration process. Identifyinginformation for the various versions (functional configurations) of themodule, e.g., functional descriptions, may be used to indicate theappropriate interface protocol. Thus, a module or cartridge 108 may havemultiple personalities or configurations with corresponding differentbitstreams for implementing the respective interface protocols for eachpersonality.

In one embodiment, the MMIP server 102A may be maintained or operated byor on behalf of the manufacturer. The MMIP server 102A may store aplurality of MMIPs for a variety of different measurement modules. Inanother embodiment, the MMIP server 102A may comprise an MMIP “clearinghouse”. In other words, the MMIP server 102A may be used by manydifferent manufacturers to register their respective measurementmodules. Thus, the MMIP server 102A may provide a central repository forMMIP programs for many different measurement modules made by a varietyof manufacturers. In one embodiment, the registration may require a fee,and so the registration information may include payment or billinginformation, such as a credit card number or billing account number.

In one embodiment, the MMIP server 102A may also be accessed by themanufacture (or other entity) to update the MMIP program(s) for themeasurement module, e.g., by providing a replacement or additionalprogram(s) for the module. The MMIP server 102A may maintain a list ofcustomers or clients and may notify the customers of updates oradditions to the MMIP programs stored on the server 102A.

FIG. 18—Method for Configuring a Measurement Module Using an MMIP Server

FIG. 18 is a flowchart of a method for configuring a measurement moduleusing an MMIP server 102A, according to one embodiment of the presentinvention. As noted above, in some embodiments, various of the steps mayoccur concurrently, in a different order than shown, or may be omitted.One or more additional steps may also be performed as desired.

In 1802, a user may install a measurement module 108. For example, theuser may insert the measurement module 108 into a slot on a carrier 110.Then, in 1804, the module 108 may provide an ID to the carrier, wherethe ID identifies the module 108. In one embodiment, the ID informationmay be stored in the EPROM 307 of the module 108, as described above.

In response to the provided ID, the MMIP server 102A may be accessed,e.g., over a network, such as the Internet, based on the ID of themodule 108, as indicated in 1804. In other words, the MMIP server 102Amay be accessed, and the ID of the module provided to the server 102A.In one embodiment, the carrier 110 may access the server 102A andprovide the ID to the server 102A. In another embodiment, the carrier110 may provide the module ID to a computer system, such as the clientcomputer system 102, and the computer system 102 may access the MMIPserver 102A and provide the module ID to the server 102A. In oneembodiment, in addition to the ID, information indicating the carrierplatform may also be provided to the MMIP server 102A, such as, forexample, information specifying whether the carrier is processor based,or FPGA based. In one embodiment, accessing the MMIP server 102A toretrieve an MMIP may require a fee, and so the information provided tothe server 102A may include payment or billing information, such as acredit card number or billing account number.

In one embodiment, the carrier 110 or the computer system 102 may accessthe server 102A to request any updates available for the MMIP of amodule. In another embodiment, the carrier 110 may request the updatethrough the computer system 102. Information indicating the version of acurrently held MMIP may be provided to the server 102A which may thendetermine whether a more recent version, or an alternative version, isavailable, and indicate this to the requester.

As indicated in 1810, in response to receiving the module ID, the MMIPserver 102A may download the appropriate program(s) to the carrier 110,according to one embodiment. In another embodiment, the MMIP server 102Amay download the appropriate program(s) to the computer system 102. Inother words, the program corresponding to the module ID and possibly thecarrier platform type (e.g., processor vs. FPGA) may be selected by theMMIP server 102A and downloaded.

Finally, in 1812, the carrier 110 may be configured with the program(s).In an embodiment where the program was downloaded to the computer system102, the computer system 102 may configure the carrier 110 with theprogram. In another embodiment, the MMIP server 102A may install theprogram directly on the carrier 110. For example, if the carrier'sfunctional unit is a processor and memory, the program may simply bestored in the memory of the carrier 110. If the carrier's functionalunit comprises a programmable hardware element, e.g., an FPGA, then thecomputer system 102 (or alternatively, the MMIP server 102A) mayconfigure the FPGA with the program, i.e., the bitstream.

In an embodiment where the program was downloaded to the carrier 110,and where the carrier's functional unit is an FPGA, a processor on thecarrier 110 may configure the FPGA with the program, i.e., thebitstream.

In one embodiment, while the program(s) are being downloaded, e.g., tothe carrier 110 or the computer system 102, an animated configurationdiagram may be displayed on the computer system 102 illustrating thetransfer of the program(s) from the server 102A to the system. Forexample, the configuration diagram may include icons representing thevarious components of the measurement system, as well as the MMIP server102A. The transfer may be represented by arrows or other symbols movingfrom the server icon to an icon representing the carrier 110 or computersystem 102, although other animated representations of the transfer arealso contemplated. Similarly, when the program(s), are being deployed onthe carrier 110, the deployment may be illustrated by the animatedconfiguration diagram, showing the bitstream or program being deployedon the carrier from or by the computer system 102.

Once the carrier 110 has been configured with the program, the carrier110 and measurement module 108 may be operable to function together,communicating in accordance with the MMIP of the module 108. Forexample, an application executing on the computer system 102 or on thecarrier 110, may invoke operation of the carrier 110 and/or module 108to perform a measurement, control, or other type of task. Exemplaryembodiments of the system described above are presented in detail belowwith reference to FIGS. 19-39

Exemplary Embodiments of the Invention

FIGS. 19-39 illustrate exemplary embodiments of the system describedabove. It is noted that the embodiments described are meant to beillustrative only, and are not intended to limit the invention to anyparticular form.

As mentioned above, the measurement modules 108 (e.g., cartridges) mayhave an interface that defines an SPI mode (with an SPI port, controlsignals, and triggering signals); an ID mode (to identify the module 108and sensors attached to it); and a pass-through digital mode (for directcontrol of digital lines). The ID mode may strictly defines the use ofthe interface, but the SPI mode may leave it flexible. Because of thisflexibility, measurement modules can be very efficient in both price andperformance, e.g., comprising only identification, signal conditioning,and ADC/DAC conversion (in the case of analog modules)—with theconverter directly controlled by the Module Interface.

The freeform nature of this interface may require the definition of aSerial Communication Block with a standardized interface to createconsistency among the various measurement modules. This SerialCommunication Block may include a mechanism (which could be implemented,for example, in VHDL, microcontroller code, or possibly in LV-FGPA ‘G’code, among others) for presenting an interface to the measurementmodule 108 that is common among different module types, described below.In various embodiments, the interface mechanism may be easilyimplementable as either soft registers in an FPGA, hard VHDL, ormicrocontroller assembly code.

FIG. 19—Communication Interfaces of the Measurement System

FIG. 19 illustrates communication layers and interfaces for themeasurement system, according to one embodiment of the invention. Morespecifically, FIG. 19 illustrates how the Serial Communication Block mayfit into a larger measurement system, according to one embodiment. Thepurpose of each layer or interface is described below, with someexamples.

Communications Layer 1902: communications physical and protocol layers,such as PCI/PXI, Ethernet/Logos, USB, serial/Modbus, among others.

Specific DAQ Interface 1904: interface for the DAQ personality. Forexample, an MIO-style personality might use FIFOs and interrupts, acontrol or FieldPoint-style personality might use most recent value dataregisters. In one embodiment, some personalities may requireconfiguration and setup register sets.

Communications Mechanism 1903: hardware and/or firmware that controlsthe Communications Layer 1902 and protocol stacks, and maps these to theDAQ Interface 1904. Examples of communications mechanisms includeNational Instruments' miniMITE, a microcontroller with Modbus stack, anda USB controller running a register-level protocol, among others.

DAQ Personality 1905: provides the mechanisms for timing, scanning,and/or controlling the DAQ functions—analogous to an STC chip on an MIO,or microcontrollers and firmware on a FieldPoint analog module, or TIOASIC on counter-timer boards.

Standard Measurement System Interface 1906: a standardized interfacethat may facilitate consistent means for triggering, sampling, andconfiguring various measurement modules. In one embodiment, theinterface may comprise an idealized ADC/DAC/register interface.

Module Interface 1908: SPI port, control lines, and trigger linesdescribed above—may provide direct control of ADCs/DACs/signalconditioning.

Serial Communication Block 1907: a mechanism for mapping the functionsand registers of the Standard Measurement System Interface 1906 to bitstreams, control lines, and trigger lines of the Module Interface 1908.This mechanism may be implemented in a variety of ways, including, forexample, FPGA logic or micro-controller assembly code, among others. Invarious embodiments, a complete description of this mechanism may beburned into the EEPROM of each module 108 or may be provide by ahigher-level “driver” layer.

Measurement Module 108: described above, the measurement module 108 maycontain just ADCs/DACs and signal conditioning functionality, or mayinclude other functionality as desired.

More detailed descriptions of these layers and interfaces are providedbelow.

Module Interface 1908, Serial Communication Block 1907, and StandardMeasurement System Interface 1906

It is noted that in a preferred embodiment of the measurement system,the Module Interface 1908, the Serial Communication Block 1907, and theStandard Measurement System Interface 1906 may be independent of theother aspects of the system, such as the DAQ Personality 1905, etc. Thisindependence may provide the flexibility to use measurement modules 108in a variety of disparate products and applications.

As mentioned above, in some embodiments, the measurement modulesthemselves may provide just the basic functions of signal conditioningand conversion (in the case of analog modules). Scanning, waveformacquisition, timing, synchronization, and other DAQ functions may beperformed independent of the measurement modules 108, e.g., as they areindependent of the ADC and DAC chips used in other measurement products,i.e., modules, cards or devices. In a complete system, information aboutthe specifics of the Module Interface 1908 (the bits transferred and theuse of the control and trigger lines) may be required in order to createthe Serial Communication Block 1907 to maintain consistency amongdifferent measurement modules. In addition, information aboutconfiguration and transfer functions of the signal conditioning may berequired to enable setup and post scaling of data. Thus, outside ofthese descriptions, the implementation of the Serial Communication Block1907 and configuration of signal conditioning, the rest of the systemmay be independent of individual measurement modules. Thus, in someembodiments, there may be no particular measurement system API ormeasurement system driver in that the rest of the system may be afunction of the personalities chosen for measurement system. Forexample, it may be possible to have an E-series measurement systemproduct (using an STC for the DAQ personality), or an NI-1200measurement system (using 8253s and control logic), or a FieldPointmeasurement system (using a microcontroller); but a preferred embodimentof the invention includes RIO-based measurement systems. The exampleproducts below indicate exemplary embodiments of how such systems mightbe put together.

Example of a PCI Board for Control Applications:

Communications layer: PCI/PXI;

Communications mechanism: National Instruments' miniMITE;

Specific DAQ interface: Configuration and setup registers; a data andstatus register per channel containing the most recently acquired inputsand next outputs to write; a trigger command to sample the inputs; atrigger command to write the outputs;

DAQ personality: An FPGA that simultaneously scans input devices on thesample trigger and writes this data to the most recent value registers;that reads the output data registers and writes their values to theoutputs on the write trigger; and that may contain digital value-addfeatures like PWM, counter, frequency input, pulse measurement, andquadrature input;

Serial Communication Block: FPGA logic that drives SPI bit streams,control lines, and trigger lines on the Module Interface to performstandard acquisition functions; and

Module Interface, measurement module: Any combination of measurementmodules with defined Module Interfaces.

Example of a USB Carrier for DAQ Applications:

Communications Layer: USB with a protocol for setting up “tasks” oracquisitions, and for streaming data;

Communications mechanism: USB slave controller (perhaps 8051 stylesimilar to USB-GPIB designs) with protocol stack and firmware toconfigure the DAQ personality for tasks and to gather and stream data;

Specific DAQ interface: Configuration and setup registers, and interrupt(or DMA as appropriate for hardware chosen) paths for passing waveformdata, perhaps similar to the interface on a LAB-PC-1200 style product;

DAQ personality: An FPGA with timers and FIFO for hardware scanning, aswell as the digital control logic for interfacing these to the SerialCommunication Blocks of the measurement system slots; also generalpurpose counter/timers and DIO lines for digital measurements;

Serial Communication Block: FPGA logic that drives SPI bit streams,control lines, and trigger lines on the Module Interface to performstandard acquisition functions; and

Module Interface, measurement module: Any combination of measurementmodules with defined Module Interfaces.

Example of a Simple RS-485 Carrier for Monitoring Applications:

Communications Layer: RS-485 with protocol like Optomux or Modbus;

Communications mechanism: Simple microcontroller with serial port andfirmware to map Optomux commands or Modbus registers to data frommeasurement system channels;

Specific DAQ interface and DAQ personality: Firmware in themicrocontroller to either read/write single data points to/from theSerial Communication Block in response to serial requests, or tocontinuously cycle through the measurement system channels and keep thelatest data points available for serial requests;

Serial Communication Block: Firmware that sequences through themicrocontroller's SPI ports and GPIO lines to control a measurementmodule; and

Module Interface, measurement module: Any combination of measurementmodules with defined Module Interfaces.

Standard Measurement System Interface 1906

In one embodiment, the Standard Measurement System Interface 1906 maycomprise an idealized interface to an ADC/DAC converter. The key to theinterface is its set of executable methods. These methods may performinitializations, change configurations, acquire single point data,acquire waveforms, and so on. Each measurement module's description maydefine the methods that it supports. A given implementation of a SerialCommunication Block 1907 may support one or many methods at a time—it isup to the particular system which of the methods available to a modulemay be supported at any given time. For example, a carrier system thatonly sends single point data on a serial link may never bother tosupport methods to allow waveform access. A small number of trigger andhandshake lines may control the flow of the method; the DAQ personalitymay connect timer or other control signals to these lines. The DAQpersonality 1905 and the Serial Communication Block 1907 may passinformation through a set of channel and data/status lines. Finally, aset of configuration registers may maintain the measurement modules'configuration states. In addition to the Standard Measurement SystemInterface 1906, in one embodiment, a mechanism to set up the methodsinside the Serial Communication Block 1907 may also be included in thesystem (dependent on the implementation).

FIG. 20—Overview of the Standard Measurement System Interface 1906

FIG. 20 illustrates a high-level architecture of the StandardMeasurement System Interface 1906, according to one embodiment of thepresent invention. It is noted that the architecture describe is meantto be exemplary only, and is not intended to limit the architecture toany particular form. Examples of interface components are heredescribed, including I/O and Flow Control Lines 2010, ConfigurationRegisters 2020, Timing Signals 2030, and Detection 2040.

I/O and Flow Control Lines 2010

Data/status: May be written and/or read, depending on the context of themethod being used. The Standard Measurement System Interface 1906 maypresent one data value (or one data/status pair) at a time, in keepingwith a tight coupling to the behavior of the module interface 1908 thatserializes accesses to the module 108. A module description format maydescribe which of these bits are data bits and which are status bits,and may further describe the mapping of the data bits to engineeringunits, and the meanings and severities of the status bits.

Strobe, Done, Trigger, Ready, Run: Control lines that may set the timingof the method being run and marshal its flow. The use of these lines isdefined below.

Channel: Indicates the next channel to be operated on in the method.

Method Select: Selects which of the supported methods to run.

Configuration Registers 2020

Configuration register: Writeable (perhaps with read back, but ameasurement module would typically not change the values) registers thatset the configuration state of the measurement modules 108.

Timing Signals 2030

Trigger Out, Oversample Clock: Direct control of the correspondingmeasurement system signals.

Detection 2040

Module Present: The level of the ID_Select line on the Module Interface1908 (when the Serial Communication Block 1907 is not otherwise drivingthis line). A high level on this line may indicate the presence of amodule 108 while a low level may indicate its absence.

Defined Methods and Operation

A number of common methods may be defined to allow typical softwareapplications and drivers to perform common tasks without requiringcustomers to be aware of the mechanisms of measurement modules 108 andSerial Communication Blocks 1907. For example, the defined methods mayinclude, but are not limited to:

Initialize: Performed on power up or reset.

Apply new configuration: Performed after new information is written tothe configuration registers to apply this configuration.

Acquire single channel: Used for single point or waveform acquisition ofa single channel, with one trigger per data point.

Acquire multiple channels: Used for single point scanning or waveformscanning across multiple channels, with one trigger per data point.

Acquire simultaneous channels: Used for single point scanning orwaveform scanning across multiple simultaneously sampled channels, withone trigger per scan.

Synchronize self-timed channels: Used to synchronize the channels of aself-timed ADC (e.g., a delta-sigma (D-S) ADC running off of theOversample Clock), with one trigger to start/synchronize the acquisitionof the channels.

Acquire self-timed synchronous channels: Used for waveform acquisitionof a single channel or waveform scanning across multiple channels of aself-timed ADC (e.g., a D-S ADC running off of the Oversample Clock)that has previously been started with the Synchronize Self-TimedChannels method, with the ADC indicating the completion of each scan.

Write single point: Used for single point update of a single channel,with one trigger to update that sample.

Write multiple points: Used for single point updates of multiplechannels or waveform generation across one or multiple channels, withone trigger per sample.

Write simultaneous channels: Used for single point or waveform updatesof multiple simultaneously updated channels, with one trigger perupdate.

These defined methods enable higher-level software, which may understandhow to deal with or even abstract these functions, to automatically mapthese functions to the behavior of that software. However, measurementmodules may also define new methods. New methods may requiremodification of higher-level software to deal gracefully with them, orthey may require a lower level of understanding among customers. Forexample, a module may be developed that defines a new method thatalternately triggers an input channel to sample and an output channel toupdate. Higher-level software may need to be aware of interleaving aninput task and an output task to make use of this new feature, orcustomers may need to understand that the trigger source alternatesbetween these functions and may need to set up low-level configurationof the DAQ personality appropriately. Either way, the ability to add newfunctions by defining new methods when necessary is provided.

Use of Methods

In general, a method may be started by setting the method select linesto choose the desired method and assert the run line 2101. Depending onthe method, the channel and/or data lines may need to be set at thispoint to indicate on which channel the method is to be started, or whatdata values to use for this channel. Then one waits for the ready lineto become asserted, indicating that the setup portion of the method isfinished. The trigger line may then be asserted to execute the timedportion of the method (for example, to take a sample) or the strobe lineto step through other portions of the method. The particular methoddefinition may dictate what behaviors the trigger or the strobe actionshave, and whether either, both, or neither actions are supported. Alsodepending on the method, the channel and/or data lines may need to bedriven to valid values to set up the next action. When the action iscomplete (perhaps indicating that data are valid and/or that the methodis ready for the next action), the done line may be asserted. When themethod is ready for the next trigger, the ready line may be assertedagain and the cycle may be repeated. To end the method, the run line maybe de-asserted.

Defined Methods

The specific actions, requirements, and behaviors of each of the definedmethods are described in the next several sections, according to oneembodiment. Additionally, a timing diagram may be presented illustratingsignaling for each method.

FIG. 21—Initialize

FIG. 21 is a timing diagram for the Initialize method, according to oneembodiment. If a module 108 supports the Initialize method, theInitialize method is preferably run after power-up or reset.

After the method select lines are set to select the Initialize methodthe run line 2101 may be asserted. The channel 2102 and data 2107 linesmay not be used for this method. The method may perform any setup stepsrequired before asserting the ready line 2103. After the ready line 2103is asserted, the trigger line 2104 may be asserted to perform theinitialization. The need for timed initialization is weak at best, butthis does provide the option of synchronizing the initialization orreset of multiple modules. When the triggered initialization is completethe done line 2105 may be asserted, after which the run line 2101 may bede-asserted to end the method.

FIG. 22—Apply New Configuration

FIG. 22 is a timing diagram for the Apply New Configuration method,according to one embodiment. If a module 108 supports the Apply NewConfiguration method, this method is preferably run after any changesare made to the configuration register to apply these changes to themodule.

After the method select lines are set to select the Apply NewConfiguration method the run line 2101 may be asserted. The channel 2102and data 2107 lines generally are not used for this method. The methodmay perform any setup steps required before asserting the ready line2103. After the ready line 2103 is asserted, the trigger line 2104 maybe asserted to apply the new configuration parameters. Simultaneouslyasserting the trigger line 2104 may synchronize the application of newconfiguration parameters of multiple modules. When the application ofthe new configuration parameters is complete the done line 2105 may beasserted, after which the run line 2101 may be de-asserted to end themethod.

FIG. 23—Acquire Single Channel

FIG. 23 is a timing diagram for the Acquire Single Channel method,according to one embodiment. If a module 108 supports this method forone or more channels, it may be used for single point or waveformacquisition of a single channel, with one trigger per data point.Multiple channels may be of course be scanned by repeatedly applyingthis method to multiple channels, however it is likely that othermethods, if supported, may be better suited to that task.

After the method select lines are set to select the Acquire SingleChannel method the run line 2101 may be asserted. The channel lines 2102may then be set to the channel to be acquired. The method may performany setup steps required before asserting the ready line 2103. After theready line 2103 is asserted, the trigger line 2104 may be asserted totrigger the A/D conversion. Simultaneously asserting the trigger line2104 on multiple modules may synchronize the sampling of a channel oneach of the modules. When the conversion is complete and the data arevalid the done line 2107 may be asserted, after which the data 2107 andstatus 2108 lines may be read. When the method is ready for the nexttrigger, the ready line 2103 may be asserted again and the cyclerepeated. Driving the trigger line 2104 with a timer may allow forwaveform acquisition, but the timer period is preferably long enough toallow the ready line 2103 to be reasserted and for the data to be readbetween triggers. A de-asserted level on the ready line 2103 when thetimer attempts to assert the trigger line 2104 may be operable to detecta too fast timer. To end the method, the run line 2101 may bede-asserted.

FIG. 24—Acquire Multiple Channels

FIG. 24 is a timing diagram for the Acquire Multiple Channels method,according to one embodiment. If a module 108 supports this method forone or more channels, it may be used for single point scanning orwaveform scanning across multiple channels, with one trigger per datapoint. Single channels may be of course be sampled by applying thismethod to only one channel, however, the Acquire Single Channel method,if supported, may be better suited to that task. (For example, theAcquire Single Channel method may not need to wait for amplifiersettling between conversions.)

After the method select lines are set to select the Acquire MultipleChannels method the run line 2101 may be asserted. The channel lines2102 may be set to the first channel to be acquired. The method mayperform any setup steps required before asserting the ready line 2103.After the ready line 2103 is asserted, the trigger line 2104 may beasserted to trigger the A/D conversion on the first channel. The channellines 2102 may preferably be set for the next channel to be converted bythe time the trigger line 2104 is asserted. Simultaneously asserting thetrigger line 2104 on multiple modules may synchronize the sampling of achannel on each of the modules. When the conversion is complete and thedata are valid the done line 2105 may be asserted, after which the data2107 and status 2108 lines may be read. When the method is ready for thenext trigger, the ready line 2103 may be asserted again and the cyclerepeated. Driving the trigger line 2104 with a timer may allow forwaveform acquisition, but the timer period is preferably long enough toallow the ready line 2103 to be reasserted, for the data to be read, andfor the next channel value to be generated between triggers. Ade-asserted level on the ready line 2103 when the timer attempts toassert the trigger line 2104 may detect a timer rate which is too fastto for the module to keep up with. To end the method, the run line 2101may be de-asserted.

FIG. 25—Acquire Simultaneous Channels

FIG. 25 is a timing diagram for the Acquire Simultaneous Channelsmethod, according to one embodiment. If a module 108 supports thismethod it may be used for single point scanning or waveform scanningacross multiple simultaneously sampled channels, with one trigger perscan. Single channels may be of course be sampled by applying thismethod to only one channel; however the Acquire Single Channel method,if supported, may be better suited to that task, especially for waveformscanning of a single channel. The trigger line 2104 may be used tosample the channels of the module, while the strobe line 2106 may beasserted once for each data point read out.

The use of this method is similar to that of the Acquire MultipleChannels method, with the exception that the trigger line 2104 maysample the data for all channels and get the data for the first sample,while subsequent channels may be read out using the strobe line 2106.After the method select lines are set to select the Acquire SimultaneousChannels method the run line 2101 may be asserted. The method mayperform any setup steps required before asserting the ready line 2103.After the ready line 2103 is asserted, the trigger line 2104 may beasserted to sample all of the input channels. The channel lines 2102 maypreferably be set for the first channel to be read by the time thetrigger line 2104 is asserted. Simultaneously asserting the trigger line2104 on multiple modules may synchronize the sampling of all of thechannels on all of the modules. When the conversion is complete and thedata are valid for the first channel, the done line 2105 may beasserted, after which the data 2107 and status 2108 lines may be read.When the method is ready to read the next channel or to be re-triggered,the ready line 2103 may be asserted again and the strobe line 2106 maybe asserted to read another channel or the trigger line 2104 may beasserted to sample all of the channels. To end the method, the run line2101 may be de-asserted. Driving the trigger line 2104 with a timer mayallow for waveform acquisition, but the timer period is preferably longenough to allow the sampling, strobing, and reading of all of thedesired channels between runs. A de-asserted level on the ready line2103 (or an incomplete read of all the channels) when the timer attemptsto assert the run line 2101 may indicate a timer rate which is too fastfor the module to keep up with.

FIG. 26—Synchronize Self-Timed Channels

FIG. 26 is a timing diagram for the Synchronize Self-Timed Channelsmethod, according to one embodiment. If a module 108 supports thismethod it may be used to synchronize the channels using self-timed ADCs(e.g., a D-S ADC running off of the Oversample Clock), with one triggerto start/synchronize the acquisition of the channels. After the channelsof module(s) are synchronously running, the Acquire Self-TimedSynchronous Channels method may be used to read the channels.

After the method select lines are set to select the SynchronizeSelf-Timed Channels method the run line 2101 may be asserted. The methodmay perform any setup steps required, then asserts the ready line 2103to indicate that the ADCs are ready for the synchronizing trigger. Thetrigger line 2104 may then be asserted to synchronize the ADCs. Drivingthe trigger line 2104 of multiple modules simultaneously may synchronizethe ADCs across the modules. After the ADCs have been synchronized, thedone line 2105 may be asserted, after which time it is safe to de-assertthe run line 2101 to end the method.

Note: It is possible that this functionality could be contained withinthe Initialize or Apply Configuration methods for a given module.However, the synchronization of D-S ADCs may take a long time, and so anindependent method may be desirable.

FIG. 27—Acquire Self-Timed Synchronous Channels

FIG. 27 is a timing diagram for the Acquire Self-Timed SynchronousChannels method, according to one embodiment. If a module 108 supportsthis method it may be used for waveform acquisition of a single channelor waveform scanning across multiple channels of a self-timed ADC (e.g.,a D-S ADC running off of the Oversample Clock) that has previously beenstarted with the Synchronize Self-Timed Channels method. The ready line2103 may indicate that the ADC has completed a scan, and the strobe line2106 may be used to read out each channel's data.

After the method select lines are set to select the Acquire Self-TimedSynchronous Channels method the run line 2101 may be asserted. Themethod may perform any setup steps required, then the ready line 2103may be asserted after the ADC indicates that it has a new set of datasampled. After the ready line 2103 is asserted, channel lines 2102 maybe set to the first channel to be read out and the strobe line 2106 maybe asserted to start reading that channel. When the channel has beenread and the data are valid for the first channel, the done line 2105may be asserted, after which the data 2107 and status 2108 lines may beread. After reading the data 2107 and status 2108 lines, the strobe 2106and channel lines 2102 may be asserted to read another channel. To endthe method, the run line 2101 may be de-asserted. It may be important tostrobe and read all the channels to be scanned before the next ADCsampling. A de-assertion of the ready line 2103 (indicating that theADC's are re-sampling) before the done line 2105 indicates that the lastchannel has been read may indicate that the data are not being read outfast enough to keep up with the ADC.

Note: The Acquire Self-Timed Synchronous Channels and the SynchronizeSelf-Timed Channels methods could be combined in one method, where thetrigger line 2104 is used to synchronize all the channels and the strobeline 2106 is used to read out the channels. However, in the preferredembodiment, two methods are used, primarily because the synchronizationof multiple D-S ADCs may take a long time, and thus may preferably beperformed separately from the acquisition method.

FIG. 28—Write Single Point

FIG. 28 is a timing diagram for the Write Single Point method, accordingto one embodiment. If a module 108 supports this method for one or morechannels, it may be used for single point update of a single channel,with one trigger to update that sample. For multiple updates in a singlemethod (waveform updates of a single channel, single point updatesacross multiple channels, or waveform updates across multiple channels)the Write Multiple Points method or the Write Simultaneous Channelsmethod may be more efficient.

After the method select lines are set to select the Write Single Pointmethod the run line 2101 may be asserted. The channel lines 2102 may beset to the channel to be updated and the data lines 2107 may be set tothe value to update with. The method may perform any setup stepsrequired before asserting the ready line 2103. After the ready line 2103is asserted, the trigger line 2104 may be asserted to trigger the D/Aupdate. Simultaneously asserting the trigger line 2104 on multiplemodules may synchronize the sampling of a channel on each of themodules. When the conversion is complete and any returning status isvalid the done line 2105 may be asserted, after which the status linesmay be read. To end the method, the run line 2101 may be de-asserted.

FIG. 29—Write Multiple Points

FIG. 29 is a timing diagram for the Initialize method, according to oneembodiment. If a module 108 supports this method for one or morechannels, it may be used for single point updates of multiple channelsor waveform generation across one or multiple channels, with one triggerper data point. Single point updates on one channel may of course beaccomplished by applying this method to only one channel, however theWrite Single Point method, if supported, may be better suited to thattask.

After the method select lines are set to select the Write MultiplePoints method the run line 2101 may be asserted. The channel lines 2102may be set to the first channel to be updated, and the data lines 2107may be set to the new value for that channel. The method may perform anysetup steps required before asserting the ready line 2103. After theready line 2103 is asserted, the trigger line 2104 may be asserted totrigger the D/A conversion on the first channel. The channel and datalines 2107 may preferably be set for the next channel to be converted bythe time the trigger line 2104 is asserted. Simultaneously asserting thetrigger line 2104 on multiple modules may synchronize the updating of achannel on each of the modules. When the conversion is complete and thestatus is valid the done line 2105 may be asserted, after which thestatus lines may be read. When the method is ready for the next trigger,the ready line 2103 may be asserted again and the cycle repeated.Driving the trigger line 2104 with a timer may allow for waveformupdates, but the timer period is preferably long enough to allow theready and done line 2105 s to be reasserted, for the status to be read,and for the next channel and data value to be generated betweentriggers. A de-asserted level on the ready line 2103 when the timerattempts to assert the trigger line 2104 may detect a timer rate whichis too fast to for the module to keep up with. To end the method, therun line 2101 may be de-asserted.

FIG. 30—Write Simultaneous Channels

FIG. 30 is a timing diagram for the Initialize method, according to oneembodiment. If a module 108 supports this method, it may be used forsingle point or waveform updates of multiple simultaneously updatedchannels, with one trigger per update. Single point or waveform updateson one channel may of course be accomplished by applying this method toonly one channel—however the Write Single Point or Write Multiple Pointmethods, if supported, may be better suited to that task.

After the method select lines are set to select the Write SimultaneousChannels method the run line 2101 may be asserted. The channel lines2102 may be set to the first channel to be updated, and the data lines2107 may be set to the new value for that channel. The method mayperform any setup steps required before asserting the ready and doneline 2105. After the done line 2105 is asserted, the status lines may beread for that channel and more channel and data pairs may be writtenwith the strobe line. After the ready line 2103 is asserted, the triggerline 2104 may be asserted to trigger the D/A conversion on all of thechannels. Simultaneously asserting the trigger line 2104 on multiplemodules may synchronize the updating of all the channels on all of themodules. When the conversion is complete and the method is ready formore data to be strobed in the done line 2105 may be asserted again andthe cycle repeated. Driving the trigger line 2104 with a timer may allowfor waveform updates, but the timer period is preferably long enough toallow the ready 2103 and done 2105 lines to be reasserted, for thestatuses to be read, and for the channel and data values to be generatedbetween triggers. If the ready line 2103 is de-asserted or if not allthe data/channel pairs have been written when the timer attempts toassert the trigger line 2104, then the timer rate may be too fast to forthe module to keep up with. To end the method, the run line 2101 may bede-asserted.

Module Interface

As mentioned above, measurement modules 108 may have an interface thatdefines an SPI mode (with an SPI port, control signals, and triggeringsignals); an ID mode (to identify the module 108 and sensors attached toit); and a pass-through digital mode (for direct control of digitallines). The signals for these modes (as well as power and groundsignals) may be contained in a 15-pin connector, 13 pins of which may bedefined. Although the specific use of the lines and the data transferredon them may be dependent on the particular measurement module, thegeneral purpose of the each of the lines may be defined.

FIG. 31—Module Interface: Pinout

FIG. 31 illustrates one embodiment of a measurement module pinoutspecification, including 11 signal lines, of which 8 are available inDIO mode. It is noted that the pinout specification is exemplary only,and is not intended to limit the pinout specification to any particularform or feature set.

Signal Descriptions

GND: Ground reference for the power and all SPI mode and ID modesignals.

Power: 4.75 to 5.25 VDC, £100 mA peak current. Inrush current maypreferably be limited to an equivalent circuit of 10 mF or less.

Sleep: Active high signal may preferably be driven low by carriers toensure normal operation on measurement modules supporting a sleep mode.When driven high, measurement modules that support a sleep mode may gointo this low power mode. In sleep mode, all signals may be ignored. TheID select pin may continue to be pulled up by the measurement module 108to indicate the presence or absence of a measurement module

ID Select: Detects presence of modules with a strong (1.5 to 3.3 kOhm)pull-up on measurement system and weak pull-down on the carrier. It maybe used as a select and frame synch line with SPI_FUNC, SPI_CLK, MISO,and MOSI to determine the type of measurement system by reading from anidentification EEPROM or to access plug-and-play sensor information. TheEEPROM may contain information about calibration, communication, andidentification of the measurement module. Plug and play information maybe stored in the sensor through a microLAN 1-wire interface.

SPI_CS: SPI Chip Select line that operates as frame sync for the SPIport. When a measurement module 108 is in SPI mode it may ignore SPI_CLKand MOSI and may not drive MISO when the SPI_CS is held high, but mayrespond to these signals when SPI_CS is low. Measurement modules mayrequire SPI_CS to go low during each byte or to stay low for groups ofbytes. SPI_CS may stay high in ID mode, as the ID Select line providesthe select and frame sync functions in this mode.

SPI_FUNC: Qualifies the SPI_CS or ID select to indicate which SPIfunction is being communicated with on the measurement module. In SPImode, these functions may be a data port (SPI_FUNC=0) and aconfiguration port (SPI_FUNC=1), but in general they are two arbitraryports that the SPI port can point to. In the ID mode, these interfacesmay be the configuration EEPROM (SPI_FUNC=1) or the smartsensor/microLAN interface (SPI_FUNC=0).

SPI_CLK: Idle high clock, data are sent on the falling edge and sampledon the rising edge.

MOSI: Master-Out, Slave-In SPI data line.

MISO: Master-In, Slave-Out SPI data line.

Convert: Triggers a converter. Starts an acquisition of an ADC or loadsa DAC or latches a shift register. The polarity and edge/levelsensitivity of this signal is not predefined, nor is it an absoluterequirement that it be used. The command set for an individual module108 may indicate the usage of this line.

Busy: Indicates the progress of an acquisition, or holds offcommunication for other purposes (such as powering up from sleep mode orwaiting for an amplifier to settle). The polarity and edge/levelsensitivity of this signal is not predefined, nor is it an absoluterequirement that it be used. The command set for an individual module108 may indicate the usage of this line.

Trig_Out: A signal generated by the measurement module 108 to act as atrigger for the rest of the system. Examples include a digital inputchannel or a comparator on an analog input channel.

Oversample Clock: An over-sampling clock for synchronizing continuouslyclocked data converters, such as D-S converters. Modules may be ableselectively clock their converters from either an internal clock or fromthis line, and they may be able to selectively drive this line with theinternal clock. In a multi-module system, one module 108 may drive thisline with its internal clock, while the carrier routes that signal toall the other modules to be synchronized with the first.

Reserved: Lines not specified yet for measurement modules. One possibleline that could be defined is a SPI_CLK_OUT line, which the measurementmodule drives as a copy of the clock, but a copy that source-synchronouswith respect to the MISO line. Defining such an SPI_CLK_OUT line mayallow for faster SPI rates. It may impact the cost of isolation byallowing slower isolators to be used on the SPI port, but it may alsorequire an additional isolator for the return clock. Other uses for thisline could be as additional power supplies (such as 3.3 V, ±10 V, 24 V)or additional select lines for added functionality, or as localcommunications between modules.

ID, SPI, and DIO Modes

All measurement modules according to the present invention preferablysupport the ID mode. The ID mode is entered whenever the ID Select lineis driven low. In the ID mode, the SPI_FUNC, SPI_CLK, MOSI, and MISOlines of the measurement module may all behave as specified for ID modeoperation. The carrier may avoid driving the SPI_CS line low during IDmode to prevent the SPI lines from attempting to access data orconfiguration interfaces.

If the configuration EEPROM indicates that the type of the interface isgeneric DIO, then (whenever the ID Select line is high) 8 lines may bemade available as generic digital I/O. If the configuration EEPROMindicates that the type of the interface is SPI, the lines may operateas indicated above.

Signal Levels, Pull-Ups, and Pull-Downs

In one embodiment, all of the module interface signals may be defined as3.3 V LVTTL compatible and 5 V tolerant. The carrier may be able to keepit's signals in a tri-state mode with no module present, and if it usespull-ups/-downs or keeper circuits they may be weak enough to beoverdriven to valid levels by module pull-ups/downs of up to 10 kOhms(pulled to either 5 V or Ground). The module 108 may use suchpull-up/-down resistors, in particular to establish proper power-upbehavior and to prevent recognition of the SPI_CS as being driven to avalid active low while the carrier holds it as a tri-state with a weekkeeper circuit or pull-up. Further information on the defined mechanismsand responsibilities for power-up behavior is provided below in thesections titled Power-Up and Hot-Swap Behavior.

FIGS. 32A and 32B—SPI Signal Timing Relationships

FIGS. 32A and 32B illustrate SPI signal timing relationships, accordingto one embodiment of the invention.

FIG. 32A—SPI Timing Relationships

FIG. 32A illustrates SPI timing relationships, according to oneembodiment. More specifically, FIG. 32A illustrates the timingrelationships between the CS, CLK, MOSI, and MISO signals, as shown.

FIG. 32B—SPI Timing

FIG. 32B illustrates SPI timing, according to one embodiment. Morespecifically, FIG. 32B illustrates SPI timing for SPI_FUNC, SPI_CS,SPI_CLK, MOSI, and MISO signals, as shown. In this embodiment, t (tau)=atime constant defined in the module's configuration EEPROM 307. A module108 may meet or require the timing constraints above for the given t.The SPI_CLK falling to MISO valid is usually the limiting factor, sonormally a carrier may add it's SPI_CLK and MISO delays to t todetermine a new time, t′. This t′ may be used as either the clockhalf-period (if the carrier samples MISO on the rising edge) or as thefull clock period (if the carrier samples MISO on the next fallingedge). Sampling MISO on the falling edge may allow for double the clockrate, but may require the carrier to generate an internal extra fallingclock edge.

FIGS. 33A-33C—Circuit Examples: Measurement Modules

FIGS. 33A-33C are diagrams of example circuits of measurement modules,according to one embodiment. It is noted that these circuits areintended to be illustrative only, and are not intended to limit thecircuitry of measurement modules to any particular form or architecture.FIG. 33A is a circuit diagram for a 4-Channel MUXed Analog Input module,according to one embodiment. FIG. 33B is a circuit diagram for an8-Channel (4 in, 4 out) Pass-Through Digital module, according to oneembodiment. FIG. 33C is a circuit diagram for a 4-Channel MUXed AnalogInput w/Analog Trigger, according to one embodiment.

FIGS. 33D-33G—Circuit Examples: Measurement Modules with RIO FPGA

FIGS. 33D-33G are diagrams of example circuits of measurement modules108 coupled to RIO FPGAs 308, according to one embodiment. In theseembodiments, RIO provides back-end functionality for the measurementmodule, providing one or more functions for control, communication,and/or processing for the module 108. It is noted that these circuitsare intended to be illustrative only, and are not intended to limit thecircuitry of measurement modules 108 and/or RIO FPGAs 308 to anyparticular form or architecture.

FIG. 33D is a circuit diagram for a simple 8-channel digital output,according to one embodiment. In this embodiment, the RIO FPGA 308operates to send digital signals via control 3340, over 8 digital lines(DIO_0-DIO_7) to the measurement module 108, which may then provide thesignals as output through 8 respective digital outputs 3330, as shown.

FIG. 33E is a circuit diagram for an 8-channel event counter, accordingto one embodiment. In this embodiment, the RIO FPGA 308 is configuredwith 8 counters 3308A-3308H which may operate to receive event signalsfrom a data bus 3350, and send count signals to the measurement module108.

FIG. 33F is a circuit diagram for a 4-channel analog input, according toone embodiment. In this embodiment, the measurement module 108 mayreceive analog signals through any of 4 analog inputs 3335 which may beconverted to digital signals and transmitted to the RIO FPGA. As FIG.33F also shows, the RIO FPGA 308 is configured with a timing block 3382to control communications with the module 108, and SPI communicationlogic 3384 to receive digital signals from the measurement module 108.The received digital signals may then be transmitted to external systems(or other components of the measurement system) via the data bus, asshown.

FIG. 33G is a circuit diagram for a 4-channel delta-sigma analog input,according to one embodiment. In this embodiment, the measurement module108 may receive analog signals through any of 4 analog inputs 3335 whichmay be converted to digital signals and transmitted to the RIO FPGA. Incontrast to the circuit of FIG. 33F, rather than MUXing the analog inputsignals, each analog input has it's own AD Converter 304, allowingdelta-sigma operations to be performed on the plurality of inputsignals. As FIG. 33G also shows, the RIO FPGA 308 is configured with atiming block 3382 to control communications with the module 108, and SPIcommunication logic 3384 to receive digital signals from the measurementmodule 108. The received digital signals may then be transmitted toexternal systems (or other components of the measurement system) via thedata bus, as shown.

FIGS. 34A-34E—Communications Over SPI

In general, communications with a measurement module 108 may includesending setup information (e.g., a channel number or, in the case of anoutput module, data) sending a trigger, waiting for a busy line, sendingcommands (e.g., to read data) and reading the response. Somerepresentative examples are presented in FIGS. 34A-34E.

FIG. 34A illustrates setup information for a simple one-channel at atime example: one trigger per channel.

FIG. 34B illustrates setup information for simultaneously sampledchannels: one trigger for all channels

FIG. 34C illustrates setup information for simultaneously sampledchannels with data and status.

FIG. 34D illustrates setup information for very simple DAC output.

FIG. 34D illustrates setup information for fast, simple ADC input.

Serial Communication Block

As mentioned above, the Serial Communication Block 1907 is the mechanismfor mapping the functions and registers of the Standard MeasurementSystem Interface 1906 to the bit streams, control lines, and triggerlines of the Module Interface. This mechanism may be implemented as FPGAlogic or as microcontroller assembly code. In general, an implementationmay consist of a firm (VHDL or compiled assembly) framework thatpresents the Standard Measurement System Interface and which can be softconfigured (for example, with configuration registers or instructionfiles) to support a specific module.

A format for describing this soft configuration may be provided (anddefined in the next section of this document) and may be kept simple andgeneric enough to allow for configuration of the Serial CommunicationBlock 1907 independent of the implementation. To allow for suchflexibility some amount of structure is needed to provide a frameworkfor this description.

Phases of a Method in the Serial Communication Block

A method may internally have three independently defined phases (orstates) in its operation. First is the setup phase, followed byrepetitions of the triggered and strobed phases. In one embodiment, anyof these phases may null—having no action.

Setup Phase

After the method is run (i.e., invoked), it may first execute its setupphase. This phase may be executed just once in a method. It may or maynot make use of channel or data information available at the time themethod is started. After the setup phase completes, the SerialCommunication Block may wait for either a trigger (in which case aninstance of the trigger phase may be run) or for a strobe (in which casean instance of the strobe phase may be run).

Trigger Phase

After the setup phase has been run, in one embodiment, the trigger phasemay be executed every time the trigger line 2104 of the StandardMeasurement System Interface is asserted. In general, the ready line2103 may be used to indicate whether the trigger phase is ready to berun. The trigger phase may be run repeatedly in a method. The triggerphase is intended to be used to control timed functions that are likelyto be controlled by a timer or other trigger source connected to thetrigger line 2104.

Strobed Phase

Like the trigger phase, the strobed phase may be first run after thesetup phase has finished. The strobed phase may execute after eachassertion of the strobe line and may be run repeatedly in a method. Ingeneral, the done line 2105 may indicate whether the strobed phase isready to run. The intention of the strobed phase is to controlnon-timing sensitive functions (like reading in or reading out data)that are unlikely to be connected to timers or other trigger sources.

Each phase may consist of a series of commands that read bytes in and/orout of the SPI port; that set the levels of the control, trigger, andflow lines of the Module Interface 1908; that wait for events on theBusy line of the Module Interface 1908; that set the states of the doneand ready lines of the Standard Measurement System Interface 1906; andthat map the done, ready, trigger, and strobe lines of the StandardMeasurement System Interface 1906 to the Convert and Busy lines of theModule Interface 1908. This series of commands may be referred to as asequence. A module 108 may have defined several sets of these sequences.For every defined method, each phase and channel combination may bemapped to one of these sequences. Thus, every time a method is run thesequence which is mapped to the setup phase for the selected method andthe selected channel may be executed. When the strobe or trigger linesare subsequently asserted the sequence that is mapped to the respectivephase for the channel value set at the time of the assertion may beexecuted.

Components of the Serial Communication Block

The firm implementation of a Serial Communication Block 1907 may consistof the following components; sequencer 3502, sequence selector 3504,sequence list 3506, signal router 3508, configuration registers 3510,scratchpad registers 3512, and pass-through mechanism 3514, described inmore detail below. A block diagram of one embodiment of the SerialCommunication Block 1907 is shown in FIG. 35, described below. The softconfiguration of a Serial Communication Block 1907 may comprise thelook-up table loaded in the sequence selector 3504, the set of commandsloaded in the sequence list 3506, and the configuration of the signalrouter 3508 in either DIO or SPI modes.

In various embodiments, the actual implementation of the SerialCommunication Block 1907 can be as VHDL or microcontroller code, anddoes not even need to strictly adhere to any particular format. However,the description format used to describe the operation of a module 108may do so in terms of these components of the Serial Communication Block1907 and in terms of the signals defined herein (or elsewhere) for theStandard Measurement System Interface 1906. Other implementations ofboth the Serial Communication Block 1907 and the Standard MeasurementSystem Interface 1906 may be valid as long as suitable mappings to thedescribed implementations are developed, thereby allowing thedescription format to still be properly interpreted.

Sequencer

In one embodiment, the sequencer 3502 may comprise a state machine orinterpreter that runs through the sequences of commands for the phasesof the methods. This component may run through the list of sequencecommands for the selected method/phase/channel combination, andinterpret and implement each of the commands in this list, sending outor reading in SPI data, setting or monitoring the states of the SPIcontrol lines and the done and ready lines of the Standard MeasurementSystem Interface 1906, and controlling the signal router 3508.

Sequence Selector

The sequence selector 3504 may hold a mapping of method/channel/phasecombinations and sequence lists. Each time a phase of a method isinitiated (by running the phase or by asserting the trigger or strobelines of the Standard Measurement System Interface 1906) the sequenceselector 3504 may select the appropriate list of commands from thesequence list 3506, point the sequencer 3502 to the first command in theselected list, and start the sequencer 3502.

Sequence List

The sequence list 3506 may comprise a set of registers (or otherimplementation specific memory file mechanism) that stores the lists ofcommands for each of the defined sequences. The sequence selector 3504may index this list using its lookup table and point the sequencer 3502to the appropriate starting position for a given phase/channel/methodcombination. Then the sequencer 3502 may step through the commands inthis sequence list.

SPI Port

In one embodiment, the Serial Communication Block 1907 may include anSPI Port 3514 that may include a shift register that sends and receivesdata through the SPI lines of the Module Interface 1908. The SPI Port3514 may control the chip selects and function select lines, and mayhave a programmable clock rate. The sequencer 3502 may control the SPIPort 3514.

Signal Router

The signal router 3508, under control of the sequencer 3502, may beoperable to map the trigger and/or strobe lines of the StandardMeasurement System Interface 1906 to the strobe line of the ModuleInterface 1908, and may map the Busy line of the Module Interface 1908to the ready and/or done lines of the Standard Measurement SystemInterface 1906. The signal router may also map the ID-Select, Trig_Out,and Oversample Clock lines of the Module Interface 1908 to the ModulePresent, Trigger Out, and Oversample Clock lines of the StandardMeasurement System Interface 1906. Finally, the router 3508 may map thedata lines of the two interfaces (3506 and 3508) for modules thatoperate in DIO mode.

Configuration Registers

In one embodiment, the configuration registers 3510 may accept and storeconfiguration data from the standard Serial Communication Block 1907 andmake this data available to the sequencer 3502 for use in generating theappropriate SPI data to send to the module 108. These registers may beimplemented as read/write registers from the Standard Measurement SystemInterface 1906 to allow for read-modify-write functions. They maypreferably be read-only from the perspective of the sequencer 3502.

Scratchpad Registers

In one embodiment, the scratchpad registers 3512 may be available asinternal, general purpose registers available to the sequencer for usein read-modify-write or transfer functions on the SPI port

Note: Reasonable size limits for the configuration registers 3510 andthe scratchpad registers 3512 need to be set. Larger configurationregisters allow for data that maps directly to bytes sent out the SPIport, which can minimize the list of commands for a sequence by allowingthe use of byte-, rather than bit-, oriented commands. On the otherhand, using bit-oriented commands can minimize the configurationregisters 3510 and make them more human-comprehensible.

Pass-through Mechanism

In one embodiment, a mechanism to provide direct access to the ModuleInterface 1908 may be needed to allow for reading of the ID informationof the module 108. This mechanism may also be used for low-level controlof modules for special applications like testing and calibration. Thismechanism may be implementation specific, and may even be implemented byloading special sequence commands in the sequence list 3506.

FIG. 35—Serial Communication Block Diagram (FPGA Implementation)

A block diagram of the Serial Communication Block 1907 is shown in FIG.35 for an FPGA implementation. The sequence list 3502, configurationregister 3510, and scratchpad registers 3512 may be simply RAM blocks,the sequence selector 3504 may be a lookup table (with logic to tell thesequencer 3502 to start), the SPI Port 3514 may be a shift register (itmay have a programmable bit rate) and the signal router 3508 may be abi-directional transceiver. The sequencer block 3502 may be the mostcomplex of the function blocks, in that it may read and implement thecommands of the sequence list 3506.

Serial Communication Block Description Format

In one embodiment, the implementation of the Serial Communication Block1907 for a particular measurement module 108 may be realized through thesoft configuration of the sequence list 3506, the sequence selector3504, and the signal router 3508. A description format of the SerialCommunication Block 1907 may only need to describe the configuration ofthese three components of the Serial Communication Block 1907. In oneembodiment, the configuration of the sequence list 3506 may simplycomprise the listing of the command codes; the configuration of thesequence selector 3504 may simply be the set of lookup values that mapchannel/phase/method combinations to indexes in the array of thesequence list 3506; and the configuration of the signal router 3508 mayonly need to be an indication of whether the Module Interface 1908 isused in SPI mode or DIO mode, and if it is in DIO mode it may need toindicate the directionality of the DIO lines.

FIG. 36—Sequence List Configuration

The sequence list component 3506 may comprise an array of commands forthe sequence to carry out. Examples of supported commands are listed inFIG. 36. These commands are presented as they are used in thedescription format. A given implementation may modify these commandsbefore loading them into the sequence list 3506 to better match with thespecific implementation of the sequencer component 3502.

Bits vs. Bytes

SPI generally only defines byte transfers, but a variant (QSPI) doesallow sub-bytes to be sent, possibly providing slightly higherperformance in some cases. However, even though some SPI devices maywork with QPSI non-byte length values, most SPI hardware implementationsin microcontrollers may be unable to send sub-bytes. Also, the SPI Portcomponent 3514 of the Serial Communication Block 1907 may be a littlesimpler to implement if it only needs to support 8-bit transfers. Thus,using byte access at the Module Interface level is probably advisable,as it may prevent possible compatibility conflicts.

Defining Communication Timing

With some care in logic and cable delays, most intended devices may workwith 1 Mbit/s SPI. However, some devices may run at 10 to 20 Mbit/s sorestricting the SPI communications to be defined at only 1 Mbit/s maysignificantly limit the potential performances of some measurementsystem designs. Therefore, there may be sequence commands in thedescription to indicate the maximum SPI rate allowed. One otherpotential problem is that some SPI devices actually have minimum SPIrates supported. Running the SPI clock too slowly may cause the deviceto reset or exhibit some other unwanted behavior. Since there is littlereason to expect that the Serial Communication Block 1907 and its SPIPort component 3514 may have problems running at the SPI clock to leasta couple of hundred kHz, this is probably not a problem. However,running through the sequence too slowly (i.e., taking too long betweenbytes) may cause self-timed ADCs (like D-S ADCs) to overwrite the datawith new data before the old data can be read.

FIG. 37—SPI Rate Description Format

FIG. 32B, described above, illustrates a method of defining the maximumtiming requirements for a measurement module, where a single value τ maydefine the timing for the module. FIG. 37 defines a set of 32 possiblevalues for τ on an approximately logarithmic scale, according to oneembodiment. This set of values may allow for rates from 20 MHz to 100kHz, with a resolution of 15-20%. The carrier may lookup the value τ,add its own timing delays, and then set the Serial Communication Block1907 to run at the next slower rate that it is capable of generating.

Note: In one embodiment, the selected value or τ may be used not only toset the SPI clock, but to also set the convert pulse time.

FIG. 38—Creating the Description File

The format for storing the set of sequence command lists may simplycomprise a listing of the commands with a header that describes whichones are used with which methods. FIG. 38 shows how this file may beconstructed, according to one embodiment. The first entry is a byteindicating the number of methods supported. This is followed by a set ofinformation for each method. The first element in this set is an ID bytethat identifies the method as one of the defined methods describedearlier in this document. The next element is a byte indicating thenumber of channels that support this method. This element is followed bya set of 4 numbers for each of those channels—the channel number and theindex of the sequence list to run for each of the three phases of amethod. (The first sequence list described in this file has an index of0, the second an index of 1, and so on . . . )

In the embodiment shown in FIG. 38, after the indexes for each phase ofeach channel of each method are listed, the next element in thestructure is a revision identifier that indicates what revision level ofthe standard the sequence commands follows. This may be followed by abyte indicating the number of unique sequence lists defined by themodule. For each of these sequence lists there may be a length fieldindicating the number of bytes of the sequence followed by those bytesof the sequence itself. After all of the sequence lists are listed, thestructure may be completed with a checksum, CRC (Cyclic RedundancyCode), or other verification mechanism.

Module Description Format

Separate from defining the Serial Communication Block 1907 (which ineffect describes the syntax of the communications interface), there maybe a Module Description Format that defines the semantics of theStandard Measurement System Interface 1906. This may include themeanings of the methods, the interpretation of the data/status fieldsfor each channel, and/or the interpretation of the configurationregisters. These semantics may be needed for both user-level informationand for the use of the system or software.

In one embodiment, the Module Description Format may provide some or allof the following information:

1. Partitioning of the configuration registers among the variouschannels (which bytes are associated with which channels);

2. Scaling of Data values to engineering units, and any dependenciesthis may have on configuration register values (such as gain settings);

3. Severity of status register values;

4. Identification of supported methods;

5. Valid values for configuration registers;

6. Meaning of configuration register values; and

7. Meaning of status register values.

The first 5 of these may be needed by the system; the last two may beused for presentation at the user-level API.

FieldPoint provides an example of the use of a standard descriptionformat for describing the semantics of a register set. One area in whichthe FieldPoint system is deficient is in defining relationships betweenchannels. For example, there is no provision for indicating to thesystem software that one channel is meant to be the cold junctionreading for the other (thermocouple) channels, or that odd channels areremote sense inputs for the even (bridge) channels, or that a onechannel is the voltage and another is the current for a power input,etc.

Identification and Description EEPROM

In one embodiment, the Module Description Format and moduleidentification information may be stored in an SPI EEPROM on each module108. The EEPROMs may be the 25xxx family of SPI EEPROMs, as made by STMicroelectronics under the part numbers M95xxx-6, in densities from 128bytes to 32 Kbytes, by Atmel under the part numbers AT25xxx-10I indensities from 128 bytes to 128 Kbytes, by Fairchild under the partnumbers FM25CxxxE in densities from 256 bytes to 8 Kbytes, by ISSI underthe IS25C family in densities from 4 Kbytes to 32 Kbytes, by Microchipunder the 25C and 25LC families in densities from 512 bytes to 8 Kbytes,or by Xicor with part numbers X25xxxI in densities from 256 bytes to 32Kbytes, although Xicor is replacing them with the X5000 family of systemmanagement parts.

EEPROM Variations

There are some variations between the different EEPROM parts that mayneed consideration. These variations may be in the maximum SPI speeds,the addressing modes, and the page sizes for writing.

EEPROM SPI Port Electrical Levels

Most EEPROM vendors use CMOS, rather than TTL, voltage input specs. Theminimum VinH of VCC×0.7 may not be compatible with the LVTTL requirementadopted for measurement system when the EEPROMs use 5.0 Volt power.Either these EEPROMs may use 3 Volt power; or the Data In, Clock, andChip Selects may be buffered; or a part may be chosen withLVTTL-compatible inputs (e.g., the Microchip parts).

EEPROM SPI Rates

ST makes its M95 family with versions at that run at 5 MHz and 2 MHz,Atmel's AT25 family runs at max speeds from 2.1 to 20 MHz depending onthe part, Fairchild's FM25C and ISSI's IS25C families run at 2.1 MHz,Microchip's 25C family runs at 3 MHz, and Xicor's X25 family runs ateither 1 or 2 MHz, with a few parts available in 5 MHz versions. Sincethe ID functions of the EEPROM may not be very time critical, the safestoption may be to support the 1 MHz version of the Xicor line (forexample, the X25040).

EEPROM Addressing Modes

All the parts in these families generally use one byte for a commandfollowed by an address. The 128, 256, and 512 byte parts in thesefamilies use one byte for the address (in the case of the 512 byte part,the most significant address bit is placed in the command byte) whilethe 1024 byte and larger parts use a two byte addressing scheme, withthe most significant byte first. To identify the type of EEPROM used,all parts using one byte addressing should have their first byteprogrammed with a dummy value of FF, and the second byte with anidentifier to indicate the size of the part (see the section on theEEPROM identification byte for the format of this byte). Parts with2-byte addressing should have this identifier in the first byte.

To determine the size and addressing mode of the EEPROM, the carrier maysend the read command, followed by two address bytes of all zeros, thenread the next data byte. If the EEPROM uses a single address byte, thenthe dummy byte may be clocked out while the second address byte is beingsent and the identification byte may be clocked out next. If the EEPROMuses two address bytes, then just the identification byte may be clockedout after the second address byte. Either way, the byte read by thecarrier is the identification byte, which indicates the size andtherefore the addressing mode of the EEPROM.

Knowing the addressing mode is generally only important to the carrierwhen writing data, or when reading from somewhere in the EEPROM otherthan the beginning. For simply reading out the description format fromthe beginning, the carrier may ignore the identification byte andcontinue clocking out data until it reaches the end of the descriptionfields.

Note: Any 1 kbyte or larger parts using one-byte addressing, and any 512byte or smaller parts using two-byte addressing, should be avoided toprevent compatibility issues.

EEPROM Page Sizes

The EEPROMs in these families generally support writes to a single byteat a time or writes to a whole page at a time. Writing to the EEPROMscan be relatively slow, as much as 10 ms per write. (Ramtron has anFM25C family of SPI FRAM memory parts that may be compatible with theseEEPROM parts but does not have the slow write speed limitation.) It cantake a long time to write very much data a byte at a time, and so pagewrites may often be preferred. However, the page size may vary dependingon both the density and manufacturer of the part. For example, the pagesize of the 512 byte part is 16 bytes from ST and Xicor, but only 8bytes from Atmel; the 1024 byte part has 32 byte pages from ST andAtmel, but only 16 from Xicor. All parts support byte mode operation,and all parts may have at least 8 byte pages, and all of these partsallow partial page writes; therefore a carrier may simply assume thatall parts may have 8 byte pages. However, if it ever becomes necessaryto program an entire 32 Kbyte part using 8 byte pages it may take aslong as 40 seconds (and nearly 3 minutes for a 128 Kbyte part). For thisreason, it may be desirable to know the actual page size for a part tospeed up programming. This can be accomplished by use the first threebytes of the EEPROM identification byte to indicate the page size.

Note: there may be some EEPROMs available (the HP series from Atmel, forexample) that ONLY support full-page writes. Since these parts require acarrier to know the page size they should not be used. Likewise, anypart with smaller than 8 byte pages should not be used, such as some ofthe smaller Fairchild parts.

EEPROM Identification Byte

The identification byte may be the first byte read from the EEPROM asdescribed in the section on EEPROM Addressing Modes. The first threebytes may indicate the page size, and the last five bytes may indicatethe EEPROM size. The page size may be represented as a 0 for 8-bytepages, 1 for 16-byte pages, 2 for 32-byte pages, up to 7 for 2048-bytepages. The EEPROM size may be represented as 7 for 128 bytes, 8 for 256bytes, 9 for 512 bytes, and so on. Thus, a 4 Kbyte part with 32 bytepages may be represented as 0x4C.

The values 0x00 and 0xFF may be reserved as invalid values to give aquick indication of an un-programmed part or an invalid read attempt.

Delta-sigma Converters

The following section describes delta-sigma converters, as used invarious embodiments of the present invention.

Delta-sigma Converter Overview

Delta-Sigma (D-S) converters typically require a continuously runningoversample clock, to which all conversions are synchronous. Althoughthis may cause problems with multiplexing and synchronizing, D-Sconverters' inherently high linearity and built-in DSP functionalitymake them particularly useful for a number of applications. Some D-SADCs trade off speed for low-noise and high resolution for use with DCanalog inputs, often with the DSP set to filter out harmonics of 50 or60 Hz line noise. Other D-S ADCs use their high linearity and theirability to set the DSP for linear, brick wall filtering to be ideal forhigh resolution, low distortion audio and dynamic measurements. It iscommon in audio applications for outputs to use D-S DACs, which providehigh resolution and low distortion outputs with quantization noise at aneasily filterable high frequency.

In the case of an analog-to-digital delta-sigma converter, theoversample clock may be some multiple of the desired update rate. Thismultiple varies depending on the type of converter, and differentfiltering options for a given converter may require different multiples.A typical D-S ADC may require a continuously running oversample clock ata multiple n of the desired update rate, and after every n of theseclocks it may assert a signal to indicate that a new sample is ready.The ADC may have its data read out before the next conversion iscomplete.

In the case of a digital-to-analog delta-sigma converter, the oversampleclock may again be some multiple of the desired data rate. As with D-SADCs, this multiple can vary between part types, and some parts maysupport different multiples. A typical stereo D-S audio DAC requiresboth the high frequency oversample clock and a data update clock. Theoversample clock may be synchronous to and at a multiple n of the dataupdate clock, although the phase relationship between these clocks cangenerally be arbitrary. The DAC may receive new data after each dataupdate clock and before the next one.

Note: Other converter types requiring special clocking do exist. Forexample, some SAR ADCs require a clock to go through the internal stepsof a conversion. However, this clock generally does not need to have anysynchronization relationship to any other system clock, and so ameasurement module 108 may be able to provide the clock internallywithout regard for system timing issues. In common practice, however,ADCs that used with measurement system either may have an internaloscillator providing the clock or may use the SPI clock for thisfunction.

Problems with Delta-sigma Converters and Measurement System

Delta-sigma converters may have three unique properties that can causeproblem areas in a measurement system. They may require oversampleclocks to be generated and synchronized with the system; data from theseconverters may be solely generated or consumed synchronously to theseclocks; and data may take time running through the DSP filters on theway through the converter.

FIG. 39—Oversample Clock Generation and Synchronization

Different D-S DACs and ADCs may require different clock frequencies fromeach other and for different clock rates. Typical oversample rates canbe 64x, 128x, 192x, 256x, 384x, or 512x. Some converters require a fixedfrequency clock, such as 32.768 kHz or 2.4576 MHz, and internallygenerate the proper divisions and filter settings through softwaresettings. Other converters require variation of the oversample clockfrequency to obtain different sample rates, and still others requirevariation of both the oversample clock rate and internal converterregisters to obtain different sample rates or filter functions. Thevarious modules and target applications may require generation of a widevariety of clocks. A typical audio DAC running at a standard 44.1 kHzfrequency may need a clock of 11.2896 MHz, while a typical DC ADC mayrequire a clock of 2.4576 MHz to internally set it's filter to reject 60Hz harmonics, and a general purpose D-S ADC may need a clock at 7.680MHz for an update rate of 20 kHz. Requiring all carriers to beresponsible for generating appropriate frequencies for each module 108and each application is a substantial burden, and virtually impossiblefor simple microcontrollers and even for many FPGAs. It may be possiblefor an FPGA to generate a clock that is “close enough” using a DLL ormaybe a simple divider, and then implement a digital interpolationfilter to resample the data at the desired rate. However, this methodmay consume FPGA resources, and may effectively introduce jitter thatadversely affects the filter characteristics and measurements of theconverter. One way to solve the problem of generating clocks specific toa particular module's target application is to put the burden on themodule 108 to provide an appropriate clock source.

The oversample clock may require synchronization with other systemfunctions, particularly with other converters. Even if two identicalmodules each use their internal oversample clocks at the “same”frequency, these clocks may drift and the modules may losesynchronization over time. This may require that modules be able todrive their converters from either their internal clock or from anexternal clock. The carriers may be able to either drive all of themodules that need to be synchronized with a single clock that thecarrier generates, or the carrier may route the clock from one module108 to the others. Using a single clock generated by the carrier has thedisadvantage mentioned above of limited frequency choices, but using onemodule 108 as a clock master has the disadvantage of effectivelyadvancing the clock of that module 108 in time relative to the othermodules. A logic implementation that delays this clock by 300 ns wouldcause phase matching errors of 1° at 10 kHz. This level of phase errormay or may not be significant compared to the normal module-to-modulephase matching errors due to pre-filter characteristics and isolatordelays. A fundamental application-level tradeoff may remain betweenhaving some amount of phase delay between modules and having availablecertain specific sample rates.

The implementation of the carrier logic, particularly in cases where amodule 108 generates the oversample clock, may likely involve statemachines that have clocks that are asynchronous to the oversample clock.This may create the potential for logic synchronization problems withinthe state machine. When the carrier attempts to synchronize multiplemodules to a single oversample clock, there may exist the very realpossibility that the state machines in the FPGA may be clocked soclosely to the oversample clock that some modules may get theirsynchronization command before the oversample clock edge while othersmay get the command after that clock edge. The result of this may bethat different modules may end up synchronized a whole oversample clockperiod apart, resulting in an apparent phase delay of one oversampleclock period.

To allow for correct synchronization of multiple D-S converter, at leastin the tightly timed case where the carrier is generating all theoversample clocks, the rising edge of the Trigger signal on the StandardMeasurement System Interface 1906 may be defined as being valid on thefalling edge of the Module Interface Oversample Clock line. This can beaccomplished by having the Trigger line [of? and?] all the measurementsystem interfaces be latched on a falling edge of Oversample Clock, thenhaving each measurement system interface latch it with the next risingedge of the Oversample Clock. This then means that D-S modules thatwould benefit from synchronization may use their Convert line as asignal to start sampling the converters with the Oversample Clock. TheSignal Router function may then connect the Trigger line on the StandardMeasurement System Interface 1906 to the Convert line on the ModuleInterface 1908 with low delays. FIG. 39 illustrates one embodiment of amechanism the carrier's logic may use to synchronize multiple D-Sconverters. It should be noted that the embodiment of FIG. 39 isillustrative only, and is not intended to limit the mechanism to anyparticular form or architecture.

Note: By requiring the Signal Router function in the SerialCommunications Block 1907 to allow routing or gating of the SPI_CSand/or SPI_FUNC, there may be more flexibility in the design of D-Smodules by removing the restriction of using the Convert line to controlconverter start-up and synchronization.

Data Synchronization

Delta-Sigma modulators typically generate or consume data strictlyaccording to the oversample clock. This may make it difficult tosynchronize data with other converters, which sample data whenever theyreceive a convert or load signal. It may be possible to resynchronizedata from a delta-sigma to another clock source by using a digitalinterpolation filter as mentioned above, but the most practical methodto keeping synchronization between delta-sigmas and traditionalconverters is to generate the oversample clock for the delta-sigmas andthe conversion clock for the other converters from the same source. Thismay involve the tradeoffs mentioned above regarding clock generation andchoosing specific sample frequencies. Once possible consequence is thatthere may exist a limited number of frequencies at which data can beread/written synchronously from both delta-sigmas and conventionalconverters.

Synchronizing delta-sigmas to each other may be much more important.This may require not only driving them from the same clock source, butalso forcing them to start their conversions at the same time. This maybe necessary both for synchronizing the converters within a module 108and for synchronizing converters in different modules. The SynchronizeSelf-Timed Channels method may provide a consistent mechanism foraccomplishing this. However, the previously discussed problems stemmingfrom a lack of synchronization between the oversample clock and thestate machine logic can cause the different converters to be off fromeach other by one oversample clock period, at least in the case whereone module 108 generates a clock that other modules consume. The fixed(and small) delay between modules stemming from this skew may not besignificant in most cases, but this problem may be preventable using thestrategy shown in FIG. 39, where the carrier generates the masteroversample clock. A potentially more significant issue is that whenthese (almost) synchronized modules are given the command to startacquiring data, some of the modules may have just finished a samplewhile others are just about to, so the first sample from differentmodules may now be a whole sample clock period off. This may be aproblem for some applications. This problem could be solved by waitinguntil all the modules provide a new data point before sampling any ofthem. The root problem of synchronizing the oversample clock with thestate machine logic is more difficult to eliminate. Even if theoversample clock and state machine clocks were perfectly synchronized,the phase relationship between the oversample clock and any othersignals on the module 108 (particularly the Busy signal which indicatesthat new data are available) could be arbitrary, especially given thepotentials for propagation delays through logic and isolators. In otherwords, even if one knew exactly when the oversample clock was occurring,one would not necessarily know at what time relative to that clock itwas safe to start conversions or to start waiting for conversions.Therefore, it may need to be left to the DAQ personality 1905 after theSerial Communication Block 1907 to handle the transfer of data, perhapsby using the suggested method of waiting for all modules to indicatethat data are ready.

Filter Settling Time

Even when the oversample clocks of the delta-sigmas in a system arederived from the same clock that creates the conversion clocks of theconventional converters in a system, the most that can be said of thevarious conversions is that they are synchronous—they are still notnecessarily simultaneous. With most conventional converters, aconversion signal indicates the time at which the analog signal matchesthe digital data. Delta-sigmas, however, may be constantly samplingtheir signals with the oversample clock and their digital data may berepresentative of the digitally filtered integration of that signal overtime. The concept of the data being valid at a given time may only applywith the resolution of that time described being considered on the orderof the data rate (or slower). This filtering aspect may be simplyinherent in delta-sigmas and may be one of the factors that need to betaken into consideration when choosing a delta-sigma for an application.This fact may also mitigate the need for particularly tight timingrelationships between delta-sigmas and conventional converters.

Power-Up and Hot-Swap Behavior

In one embodiment, carriers 110 may maintain the module interface in atri-stated mode until they detect (from the ID_Select line) theattachment of a module 108. The carrier 110 may then identify the module108 using the ID mode of the Module Interface 1908. After a successfulidentification, the carrier 110 may then configure the module 108 usingsettings that are stored in the carrier 110 or using factory defaultsettings that are stored in the module 108. During the period betweenthe module 108 having power applied and the carrier 110 configuring itto its power up state, the modules 108 may have the responsibility topower up (glitch free) in as “innocuous” a state as possible-usually ahigh impedance state or the power-off state (which preferably may beidentical).

Module Detection using ID Select

In one embodiment, the carrier 110 may use the pull-up (1.5 kW to 3.3kW) on the ID_Select line of each module 108 to detect the presence orabsence of a module 108. The carrier 110 preferably has a weak pull-downon the line. If the carrier 110 detects a low value on the line (nomodule), then it may tri-state all of its other signal lines to thatmodule. When a carrier 110 detects the line changing from a low to ahigh (a module insertion) it may begin reading the ID EEPROM of themodule 108 by first driving the SPI_CLK line to the idle state, thenasserting the ID_Select line, then enabling the SPI_Func and SPI_MOSIlines. The carrier 110 may then read the EEPROM in the normal manner.

If the EEPROM read fails (either a 0x00 or 0xFF is read in the EEPROMidentification byte or an invalid checksum is encountered) then thecarrier may tri-state SPI_Func and SPI_MOSI lines while still holdingthe ID_Select line low, then tri-state the ID_Select line. If theID_Select line is pulled high by the module 108 then the carrier mayre-attempt an EEPROM read by asserting the ID_Select line, enabling theSPI_Func and SPI_MOSI lines, and read the EEPROM from the beginningagain. If instead the ID_Select line remains low then the carrier mayalso tri-state SPI_CLK and remain in this idle state until it detectsthat the ID_Select line is high again.

Powering Up a Module After Identification

After successfully reading the EEPROM, the carrier 110 may return theinterface 1908 from the ID mode to the normal operating mode, either SPImode or DIO mode. If the module 108 uses the DIO interface, then theSPI_Func and SPI_MOSI lines may first be tri-stated (while the ID_Selectline is still held low), then the ID_Select line may be driven high.Then the carrier 110 may drive any output lines to the desired power-upstates for that module 108. During the period where the carrier 110tri-states the signal lines and drives ID_Select high (or tri-statesID_Select during the Module Detection procedure) it may be theresponsibility of the module 108 to keep all of the outputs in the“innocuous” or power-down state. In one embodiment, the responsibilityof the carrier is to never drive the 8 DIO lines as SPI mode valuesunless it is driving ID_Select low. The modules 108 may pull up or downthese eight lines with resistors as large as 10 kOhm; therefore, thecarriers 110 may use keeper circuits or weak pull-ups that can beovercome by resistances as high as 10 kOhm to either 5V or Ground.

If the module 108 uses the SPI interface rather than the DIO interface,then the carrier 110 may exit ID mode by simply driving the ID_Selectline high. The carrier 110 may continue to drive SPI_Func, SPI_MOSI, andSPI_CLK; and it may drive the SPI_CS line to the idle (high) state. Themodule 108 may be responsible for ignoring the SPI_CS line during the IDmode when the carrier 110 is not driving SPI_CS. If the module 108 doesthis with a pull-up resistor, this resistor may be no larger than 10kOhm to allow it to overcome the weak pull-ups or keeper circuits thatthe carrier 110 may use while it tri-states the line.

After a carrier 110 takes a module 108 that uses the SPI mode interfaceout of the ID mode, the carrier 110 may load the configuration registersof the Serial Communications Block 1907 with the desired power upsettings, and then run the Initialize Method (if supported by themodule).

Power-up Settings

The context in which a module 108 powers up may affect the settings thatthe carrier should apply to the output values and configuration registervalues. The first priority is the Hot-Swap case: if a module 108B isdetected as being inserted into a location that had previously heldanother module 108A with which it is hot-swap compatible (matchingHot-Swap IDs), then the new module 108B may be powered up with thesettings of the previous module. If the new module 108 is not hot-swapcompatible, or if there was no previous module, the next priority forassigning power up settings are user-defined values. If the carrier 110has been programmed with specific power up settings or sequences for amodule 108 of a type that matches that of the new module 108B, then thatnew module 108B may be powered up with those programmed settings orsequences. If the new module's type does not match with any user-definedpower up settings, then the option of last resort is to power up themodule 108B with the factory default settings as stored in the module'sidentification EEPROM.

Factory Defaults

A set of factory default power-up settings may be stored in theidentification EEPROM of each measurement module. These settings mayinclude the static default values (0 or 1) of a DIO mode digital moduleor the configuration register settings, default output data values,and/or an initialization method for an SPI mode module. In the absenceof any other power-up setting information, the carrier 110 may use thesefactory default values as indicated in the previous section.

Hot-Swapping

When a carrier 110 detects the removal of a module, the carrier 110 maydisable the module interface 1908 by tri-stating the interface lines.However, the carrier 110 may remember the last state (configurationregister settings and output values) of the module. If the carrier 110later detects in that location a module 108 with the same Hot-Swapidentifier in its Identification EEPROM, then the carrier 110 mayreconfigure this module 108 with the settings of the previous module,rather than with the factory default settings. This may allowreplacement of module 108 without requiring user intervention toreconfigure the module. Depending on the intended use and design of thecarrier 110, the carrier 110 may allow modification of the module'ssettings (output values and configuration register settings) while themodule 108 is missing, so that on its replacement the power-up state ofthe module 108 may reflect any modifications that have occurred duringits absence.

User-Definable Power-Up Settings

It may be possible to program a carrier with user-definable power-upsettings that override the pre-defined factory default settings. At aminimum, these settings may be associated with a particular Hot-Swapidentifier and may include configuration register settings and outputvalues. If a carrier 110 detects that a new module's Hot-Swap identifiermatches with a hot-swap identifier for which user-defined power-upsettings have been stored then the carrier 110 may apply those settingsto the new module. It may even be possible for a carrier 110 to allow,in addition to static output values, programming of a power-up sequence.This may include a timed sequencing digital module or a waveform outputof an analog module. The existence and complexity of power up sequencingdepends on the needs and capabilities of the particular carrier 110.

Power-up Delays

Between the time that the carrier 110 receives power from the moduleinterface 1908 and the time that the carrier 110 has completed itspower-up configuration of that module 108, the module 108 may have theresponsibility to maintain its outputs in as innocuous a state aspossible. In addition, it may be the responsibility of these modules 108to maintain the states of their outputs in an innocuous state wheneverthey are not receiving power from the module interface 1908—even if themodule's output stages are receiving field power from the frontconnector. In addition to being innocuous, both this power-off state andthe interim power-up state may be the same state if possible, such thatthe delay time until the carrier can properly configure the module 108may manifest itself only as a lengthening of the powered-down state,rather than as an interim alternate state. Keeping the state innocuousmeans that the outputs are in what may be a relatively safe state duringthe powered-off or powering-up states.

In general, an innocuous state is a high impedance state in which theoutputs are neither driven nor clamped to each other or to anyparticular voltage. (Clamping to voltages outside the specifiedoperating ranges may be acceptable both in powered-off states as well aspowered-on.) There may be some cases, particularly with analog voltageoutput designs, where it may add significant cost to guarantee that theoutputs present a high impedance across the operating voltage range. Inthese cases, a second-best choice of an innocuous state may be aclamping or driving to ground.

There may be exceptions to these rules for specific modules. Forexample, it may be beneficial to offer versions of modules with normallyclosed (Form B) relays or discrete outputs, or even latchingrelays/discrete outputs that maintain their last states. Certainspecialty modules, e.g., bus-powered communication designs, may have aninnocuous state that is defined as being driven or clamped to particularlevels.

Thus, various embodiments of the systems and methods disclosed hereinmay provide means for a measurement module to communicate interfaceprotocol information to a carrier unit (or computer system), and for thecarrier unit to be programmed to implement the communicated interfaceprotocol. This “adaptive interface” approach allows measurement modulesto include only those components necessary for providing the requiredfunctionality, i.e., the measurement module does not have to includehardware and software implementing standard interfaces for communicationwith external systems. Additionally, the carrier unit may supportmultiple different interface protocols for communication with respectivemeasurement modules, either sequentially, or in parallel. Finally, aplurality of interface protocols may be stored on a server computersystem and made available for downloading to client computer systems.

Although the system and method of the present invention has beendescribed in connection with the preferred embodiment, it is notintended to be limited to the specific form set forth herein, but on thecontrary, it is intended to cover such alternatives, modifications, andequivalents, as can be reasonably included within the spirit and scopeof the invention as defined by the appended claims.

1. A system, comprising: a measurement module, comprising: measurementcircuitry, wherein the measurement circuitry is operable to perform oneor more of signal conditioning and signal conversion; and interfacecircuitry, wherein the interface circuitry is operable to provide aninterface for the measurement circuitry; and a carrier unit, operable tocouple to the interface circuitry of the measurement module; wherein theinterface circuitry is operable to communicate an interface protocoldescribing the interface; wherein the carrier unit comprises one or morefunctional units which are programmable to interface with themeasurement module in accordance with the communicated interfaceprotocol; and wherein the measurement module and the programmed carrierunit are together operable to perform as one or more of a DAQ device, ameasurement device, and a control device.
 2. The system of claim 1,wherein the interface circuitry is operable to communicate the interfaceprotocol to the carrier unit; the system further comprising: a computersystem which is operable to couple to the carrier unit, wherein thecarrier unit is operable communicate the interface protocol to thecomputer system; and wherein the computer system is operable to programthe one or more functional units to interface with the measurementmodule in accordance with the communicated interface protocol.
 3. Thesystem of claim 2, wherein the computer system is operable to couple tothe carrier unit over a network.
 4. The system of claim 2, wherein thecomputer system comprises a Personal Digital Assistant (PDA).
 5. Thesystem of claim 1, wherein the carrier unit includes a processor,wherein the processor is operable to program the one or more functionalunits to interface with the measurement module in accordance with thecommunicated interface protocol.
 6. The system of claim 1, furthercomprising: a computer system which is operable to couple to the carrierunit; wherein the interface circuitry is operable to communicate theinterface protocol to the computer system; and wherein the computersystem is operable to program the one or more functional units tointerface with the measurement module in accordance with thecommunicated interface protocol.
 7. The system of claim 1, furthercomprising: a computer system which is operable to couple to the carrierunit; wherein the computer system comprises a processor and a memory;wherein the memory stores a measurement program which implements one ormore measurement functions; wherein the memory also stores a softwareprogram which is executable to deploy the measurement program on the oneor more functional units comprised in the carrier unit; and wherein, inresponse to said deployment, the carrier unit is operable to perform theone or more measurement functions.
 8. The system of claim 7, wherein themeasurement program comprises a graphical program, and wherein thegraphical program comprises a plurality of interconnected nodes whichvisually indicate functionality of the graphical program.
 9. The systemof claim 7, wherein the computer system further comprises a computerdisplay; and wherein the memory also stores a software program which isexecutable to display configuration diagram of the system; and whereinthe software program is further executable to display an animation ofthe deployment of the measurement program on the carrier unit in theconfiguration diagram of the system.
 10. The system of claim 1, whereinthe carrier unit comprises one or more of a networked measurement andcontrol device, and a networked data acquisition device.
 11. The systemof claim 10, wherein carrier unit comprises one or more of an Ethernetcarrier, a USB carrier, and a wireless carrier.
 12. The system of claim1, wherein the carrier unit comprises a measurement and control system.13. The system of claim 12, wherein the measurement and control systemcomprises an industrial programmable logic controller, comprising one ormore of a real time controller and an embedded controller.
 14. Thesystem of claim 12, wherein the measurement and control system comprisesa PC based measurement and control system.
 15. The system of claim 14,wherein the PC based measurement and control system comprises one ormore of a real time controller and an embedded controller.
 16. Thesystem of claim 13, wherein the carrier unit comprises one or more of aPCI carrier and a PXI carrier.
 17. The system of claim 1, wherein thecarrier unit comprises a DAQ-in-cable.
 18. The system of claim 1,wherein the carrier unit is comprised in a PC based measurement andcontrol system.
 19. The system of claim 1, wherein the carrier unitcomprises or is comprised in a Personal Digital Assistant (PDA).
 20. Thesystem of claim 1, wherein the carrier unit further comprises: achassis; a backplane comprised in the chassis providing for electricalcommunication; and one or more slots comprised in the chassis, whereineach of the one or more slots includes a connector that is coupled tothe backplane, wherein each of the one or more slots is adapted forreceiving the measurement module or another different measurementmodule.
 21. The system of claim 1, wherein the measurement module has asmall form factor.
 22. The system of claim 1, wherein the measurementmodule has dimensions of approximately 1 inch by 2 inches by 3 inches orless.
 23. The system of claim 1, wherein the measurement module hasdimensions of approximately 0.2 inches by 1 inch by 1 inch or more. 24.The system of claim 1, wherein at least one of the functional units ofthe carrier unit comprises a programmable hardware element which isconfigurable to implement the interface protocol.
 25. The system ofclaim 24, wherein the programmable hardware element comprises a FieldProgrammable Gate Array (FPGA).
 26. The system of claim 1, wherein atleast one of the functional units of the carrier unit comprises: aprocessor; and a memory coupled to the processor; wherein the processoris operable to execute software instructions from the memory toimplement the interface protocol.
 27. The system of claim 1, furthercomprising: a sensor, operable to couple to the measurement module;wherein the sensor is further operable to send sensor signals to themeasurement module for one or more of signal conditioning and signalconversion.
 28. The system of claim 1, wherein performing signalconditioning comprises performing one or more of protection, isolation,filtering, amplification, and excitation; and wherein performing signalconversion comprises one or more of analog to digital (A/D) conversionand digital to analog (D/A) conversion.
 29. The system of claim 1,wherein the measurement module comprises a sensor; and wherein themeasurement module is operable to perform one or more of signalconditioning and signal conversion on sensor signals received from thesensor.
 30. The system of claim 1, further comprising: an actuator,operable to couple to the measurement module; wherein the actuator isfurther operable to receive control signals from the measurement moduleand perform an action based on the received control signals.
 31. Thesystem of claim 1, wherein the interface circuitry being operable tocommunicate the interface protocol comprises the interface circuitrybeing operable to communicate the interface protocol to the carrier unitupon one or more of attachment of the measurement module to the carrierunit, reset of the measurement module, reset of the carrier unit, rebootof the measurement module, and reboot of the carrier unit.
 32. Thesystem of claim 1, wherein the interface circuitry being operable tocommunicate the interface protocol comprises the interface circuitrybeing operable to communicate an ID to the carrier unit; the systemfurther comprising: a computer system which is operable to couple to thecarrier unit, wherein the carrier unit is operable communicate the ID tothe computer system; wherein the computer system is operable to retrievethe interface protocol based on the ID; and wherein the computer systemis operable to program the one or more functional units to interfacewith the measurement module in accordance with the communicatedinterface protocol.
 33. The system of claim 32, wherein the computersystem is operable to retrieve the interface protocol from a centraldatabase based on the ID.
 34. The system of claim 33, wherein thecentral database is comprised on a server computer accessible by thecomputer system.
 35. The system of claim 1, the system furthercomprising: a computer system which is operable to couple to the carrierunit; wherein the interface circuitry being operable to communicate theinterface protocol comprises the interface circuitry being operable tocommunicate an ID to the computer system; wherein the computer system isoperable to retrieve the interface protocol based on the ID; and whereinthe computer system is operable to program the one or more functionalunits to interface with the measurement module in accordance with thecommunicated interface protocol.
 36. The system of claim 35, wherein thecomputer system is operable to retrieve the interface protocol from acentral database based on the ID.
 37. The system of claim 36, whereinthe central database is comprised on a server computer accessible by thecomputer system over a network.
 38. The system of claim 1, wherein theinterface circuitry being operable to communicate the interface protocolcomprises the interface circuitry being operable to communicate an ID tothe carrier unit; wherein the carrier unit is operable to retrieve theinterface protocol based on the ID; wherein the carrier unit includes aprocessor, wherein the processor is operable to program the one or morefunctional units to interface with the measurement module in accordancewith the interface protocol.
 39. The system of claim 38, wherein thecarrier unit is operable to retrieve the interface protocol from acentral database based on the ID.
 40. The system of claim 39, whereinthe central database is comprised on a server computer accessible by thecarrier over a network.
 41. A measurement module, comprising:measurement circuitry, wherein the measurement circuitry is operable toperform one or more of signal conditioning and signal conversion; andinterface circuitry, wherein the interface circuitry is operable toprovide an interface for the measurement circuitry; wherein theinterface circuitry is operable to couple to a carrier unit, and whereinthe interface circuitry is operable to communicate an interface protocolto the carrier unit describing the interface; wherein the interfacecircuitry is operable to communicate signals with the carrier unit inaccordance with the communicated interface protocol; wherein themeasurement module is operable to perform as at least a portion of oneor more of a measurement device, and a control device.
 42. Themeasurement module of claim 41, wherein the carrier unit comprises oneor more functional units which are programmable to interface with themeasurement module in accordance with the communicated interfaceprotocol; and wherein the measurement module and the programmed carrierunit are together operable to perform as one or more of a measurementdevice, and a control device.
 43. The measurement module of claim 41,wherein the measurement module has a small form factor.
 44. Themeasurement module of claim 41, wherein the measurement module hasdimensions of approximately 1 inch by 2 inches by 3 inches or less. 45.The measurement module of claim 41, wherein the measurement module hasdimensions of approximately 0.2 inches by 1 inch by 1 inch or more. 46.The measurement module of claim 41, wherein the measurement module isfurther operable to couple to a sensor; and wherein the sensor isoperable to send sensor signals to the measurement module for one ormore of signal conditioning and signal conversion.
 47. The measurementmodule of claim 41, wherein performing signal conditioning comprisesperforming one or more of protection, isolation, filtering,amplification, and excitation.
 48. The measurement module of claim 41,wherein performing signal conversion comprises one or more of analog todigital (A/D) conversion and digital to analog (D/A) conversion.
 49. Themeasurement module of claim 41, wherein the measurement module comprisesa sensor; and wherein the measurement module is operable to perform oneor more of signal conditioning and signal conversion on sensor signalsreceived from the sensor.
 50. The measurement module of claim 41,wherein the interface circuitry being operable to communicate theinterface protocol to the carrier unit describing the interfacecomprises the interface circuitry being operable to communicate theinterface protocol to the carrier unit upon one or more of attachment ofthe measurement module to the carrier unit, reset of the measurementmodule, reset of the carrier unit, reboot of the measurement module, andreboot of the carrier unit.
 51. A system, comprising: a measurementmodule, comprising: measurement circuitry, wherein the measurementcircuitry is operable to perform one or more of signal conditioning andsignal conversion; and interface circuitry, wherein the interfacecircuitry is operable to provide an interface for the measurementcircuitry; and a carrier unit, operable to couple to the interfacecircuitry of the measurement module; wherein the interface circuitry isoperable to communicate an identifier (ID) for the measurement module,and wherein the ID is usable to reference an interface protocoldescribing the interface; wherein the carrier unit comprises one or morefunctional units which are programmable to interface with themeasurement module in accordance with the interface protocol; andwherein the measurement module and the programmed carrier unit aretogether operable to perform as one or more of a DAQ device, ameasurement device, and a control device.
 52. The system of claim 51,wherein the interface circuitry is operable to communicate the ID to thecarrier unit; the system further comprising: a computer system which isoperable to couple to the carrier unit, wherein the carrier unit isoperable communicate the ID to the computer system; and wherein thecomputer system is operable to reference the interface protocol based onthe communicated ID and program the one or more functional units tointerface with the measurement module in accordance with the interfaceprotocol.
 53. The system of claim 52, wherein the computer system isoperable to couple to the carrier unit over a network.
 54. The system ofclaim 52, wherein the computer system comprises a Personal DigitalAssistant (PDA).
 55. The system of claim 51, wherein the carrier unitincludes a processor, wherein the processor is operable to program theone or more functional units to interface with the measurement module inaccordance with the referenced interface protocol.
 56. The system ofclaim 51, wherein the carrier unit stores a database of interfaceprotocols, and wherein the carrier unit is operable to retrieve theinterface protocol from the database based on the ID.
 57. The system ofclaim 51, further comprising: a computer system which is operable tocouple to the carrier unit; wherein the computer system comprises aprocessor and a memory; wherein the memory stores a measurement programwhich implements one or more measurement functions; wherein the memoryalso stores a software program which is executable to deploy themeasurement program on the one or more functional units comprised in thecarrier unit; and wherein, in response to said deployment, the carrierunit is operable to perform the one or more measurement functions. 58.The system of claim 57, wherein the measurement program comprises agraphical program, and wherein the graphical program comprises aplurality of interconnected nodes which visually indicate functionalityof the graphical program.
 59. The system of claim 57, wherein thecomputer system further comprises a computer display; and wherein thememory also stores a software program which is executable to displayconfiguration diagram of the system; and wherein the software program isfurther executable to display an animation of the deployment of themeasurement program on the carrier unit in the configuration diagram ofthe system.
 60. The system of claim 51, wherein the carrier unitcomprises one or more of a networked measurement and control device, anda networked data acquisition device.
 61. The system of claim 60, whereincarrier unit comprises one or more of an Ethernet carrier, a USBcarrier, and a wireless carrier.
 62. The system of claim 51, wherein thecarrier unit comprises a measurement and control system.
 63. The systemof claim 62, wherein the measurement and control system comprises anindustrial programmable logic controller, comprising one or more of areal time controller and an embedded controller.
 64. The system of claim62, wherein the measurement and control system comprises a PC basedmeasurement and control system.
 65. The system of claim 64, wherein thePC based measurement and control system comprises one or more of a realtime controller and an embedded controller.
 66. The system of claim 63,wherein the carrier unit comprises one or more of a PCI carrier and aPXI carrier.
 67. The system of claim 51, wherein the carrier unitcomprises a DAQ-in-cable.
 68. The system of claim 51, wherein thecarrier unit is comprised in a PC based measurement and control system.69. The system of claim 51, wherein the carrier unit comprises or iscomprised in a Personal Digital Assistant (PDA).
 70. The system of claim51, wherein the carrier unit further comprises: a chassis; a backplanecomprised in the chassis providing for electrical communication; and oneor more slots comprised in the chassis, wherein each of the one or moreslots includes a connector that is coupled to the backplane, whereineach of the one or more slots is adapted for receiving the measurementmodule or another different measurement module.
 71. The system of claim51, wherein the measurement module has a small form factor.
 72. Thesystem of claim 51, wherein the measurement module has dimensions ofapproximately 1 inch by 2 inches by 3 inches or less.
 73. The system ofclaim 51, wherein the measurement module has dimensions of approximately0.2 inches by 1 inch by 1 inch or more.
 74. The system of claim 51,wherein at least one of the functional units of the carrier unitcomprises a programmable hardware element which is configurable toimplement the interface protocol.
 75. The system of claim 74, whereinthe programmable hardware element comprises a Field Programmable GateArray (FPGA).
 76. The system of claim 51, wherein at least one of thefunctional units of the carrier unit comprises: a processor; and amemory coupled to the processor; wherein the processor is operable toexecute software instructions from the memory to implement the interfaceprotocol.
 77. The system of claim 51, further comprising: a sensor,operable to couple to the measurement module; wherein the sensor isfurther operable to send sensor signals to the measurement module forone or more of signal conditioning and signal conversion.
 78. The systemof claim 51, wherein performing signal conditioning comprises performingone or more of protection, isolation, filtering, amplification, andexcitation; and wherein performing signal conversion comprises one ormore of analog to digital (A/D) conversion and digital to analog (D/A)conversion.
 79. The system of claim 51, wherein the measurement modulecomprises a sensor; and wherein the measurement module is operable toperform one or more of signal conditioning and signal conversion onsensor signals received from the sensor.
 80. The system of claim 51,further comprising: an actuator, operable to couple to the measurementmodule; wherein the actuator is further operable to receive controlsignals from the measurement module and perform an action based on thereceived control signals.
 81. The system of claim 51, wherein theinterface circuitry being operable to communicate the ID comprises theinterface circuitry being operable to communicate the ID to the carrierunit upon one or more of attachment of the measurement module to thecarrier unit, reset of the measurement module, reset of the carrierunit, reboot of the measurement module, and reboot of the carrier unit.82. The system of claim 51, wherein the interface circuitry beingoperable to communicate the ID comprises the interface circuitry beingoperable to communicate the ID to the carrier unit; the system furthercomprising: a computer system which is operable to couple to the carrierunit, wherein the carrier unit is operable communicate the ID to thecomputer system; wherein the computer system is operable to retrieve theinterface protocol based on the ID; and wherein the computer system isoperable to program the one or more functional units to interface withthe measurement module in accordance with the interface protocol. 83.The system of claim 82, wherein the computer system is operable toretrieve the interface protocol from a central database based on the ID.84. The system of claim 83, wherein the central database is comprised ona server computer accessible by the computer system.
 85. The system ofclaim 51, the system further comprising: a computer system which isoperable to couple to the carrier unit; wherein the interface circuitrybeing operable to communicate the ID comprises the interface circuitrybeing operable to communicate the ID to the computer system; wherein thecomputer system is operable to retrieve the interface protocol based onthe ID; and wherein the computer system is operable to program the oneor more functional units to interface with the measurement module inaccordance with the interface protocol.
 86. The system of claim 85,wherein the computer system is operable to retrieve the interfaceprotocol from a central database based on the ID.
 87. The system ofclaim 86, wherein the central database is comprised on a server computeraccessible by the computer system over a network.
 88. The system ofclaim 51, wherein the interface circuitry being operable to communicatethe ID comprises the interface circuitry being operable to communicatethe ID to the carrier unit; wherein the carrier unit is operable toretrieve the interface protocol based on the ID; wherein the carrierunit includes a processor, wherein the processor is operable to programthe one or more functional units to interface with the measurementmodule in accordance with the interface protocol.
 89. The system ofclaim 88, wherein the carrier unit is operable to retrieve the interfaceprotocol from a central database based on the ID.
 90. The system ofclaim 89, wherein the central database is comprised on a server computeraccessible by the carrier over a network.
 91. A measurement module,comprising: measurement circuitry, wherein the measurement circuitry isoperable to perform one or more of signal conditioning and signalconversion; and interface circuitry, wherein the interface circuitry isoperable to provide an interface for the measurement circuitry; whereinthe interface circuitry is operable to couple to a carrier unit, andwherein the interface circuitry is operable to communicate an identifier(ID) to the carrier unit, wherein the ID is usable to reference aninterface protocol describing the interface; wherein the interfacecircuitry is operable to communicate signals with the carrier unit inaccordance with the referenced interface protocol; and wherein themeasurement module is operable to perform as at least a portion of oneor more of a measurement device, and a control device.
 92. Themeasurement module of claim 91, wherein the carrier unit comprises oneor more functional units which are programmable to interface with themeasurement module in accordance with the referenced interface protocol;and wherein the measurement module and the programmed carrier unit aretogether operable to perform as one or more of a measurement device, anda control device.
 93. The measurement module of claim 91, wherein themeasurement module has a small form factor.
 94. The measurement moduleof claim 91, wherein the measurement module has dimensions ofapproximately 1 inch by 2 inches by 3 inches or less.
 95. Themeasurement module of claim 91, wherein the measurement module hasdimensions of approximately 0.2 inches by 1 inch by 1 inch or more. 96.The measurement module of claim 91, wherein the measurement module isfurther operable to couple to a sensor; and wherein the sensor isoperable to send sensor signals to the measurement module for one ormore of signal conditioning and signal conversion.
 97. The measurementmodule of claim 91, wherein performing signal conditioning comprisesperforming one or more of protection, isolation, filtering,amplification, and excitation.
 98. The measurement module of claim 91,wherein performing signal conversion comprises one or more of analog todigital (A/D) conversion and digital to analog (D/A) conversion.
 99. Themeasurement module of claim 91, wherein the measurement module comprisesa sensor; and wherein the measurement module is operable to perform oneor more of signal conditioning and signal conversion on sensor signalsreceived from the sensor.
 100. The measurement module of claim 91,wherein the interface circuitry being operable to communicate the ID tothe carrier unit comprises the interface circuitry being operable tocommunicate the ID to the carrier unit upon one or more of attachment ofthe measurement module to the carrier unit, reset of the measurementmodule, reset of the carrier unit, reboot of the measurement module, andreboot of the carrier unit.